Thistle, Utah

Thistle is a ghost town in Spanish Fork Canyon in southeastern Utah County, Utah, United States.[1] During the era of steam locomotives, the town's primary industry was servicing trains for the Denver and Rio Grande Western Railroad (often shortened to D&RG, D&RGW, or Rio Grande). The fortunes of the town were closely linked with those of the railroad until the changeover to diesel locomotives, when the town started to decline.

In April 1983, a massive landslide (specifically a complex earthflow[3]) dammed the Spanish Fork River.[4] The residents were evacuated as nearly 65,000 acre feet (80,000,000 m3) of water backed up, flooding the town. Thistle was destroyed; only a few structures were left partially standing. Federal and state government agencies have said this was the most costly landslide in United States history,[5][6] the economic consequences of which affected the entire region. The landslide resulted in the first presidentially declared disaster area in Utah.[5][7]

U.S. Route 6 (US‑6), U.S. Route 89 (US‑89) and the railroad (now part of Union Pacific Railroad's Central Corridor) were closed for several months, until they were rebuilt on a higher alignment overlooking the area. The remains of Thistle are visible from a view area along US‑89 or from the California Zephyr passenger train.

Thistle, Utah
Remnants of the Thistle schoolhouse, September 2006
Remnants of the Thistle schoolhouse, September 2006
Map of Utah showing a pin for Thistle near the center of the state
Map of Utah showing a pin for Thistle near the center of the state
Location of Thistle within the State of Utah
Map of Utah showing a pin for Thistle near the center of the state
Map of Utah showing a pin for Thistle near the center of the state
Thistle (the United States)
Coordinates: 39°59′29″N 111°29′54″W / 39.99139°N 111.49833°WCoordinates: 39°59′29″N 111°29′54″W / 39.99139°N 111.49833°W
CountryUnited States
Named forThistle
Elevation5,043 ft (1,537 m)
Zip code
GNIS feature ID1439662[1]


Thistle is about 65 miles (105 km) southeast of Salt Lake City, at the confluence of the two primary tributaries to the Spanish Fork River, Thistle Creek and Soldier Creek.[8] This confluence, at an elevation of 5,043 feet (1,537 m),[1] is also the junction of two naturally formed routes across the mountains of central Utah. The primary route crosses the Wasatch Mountains, via the Wasatch Plateau and Soldier Summit. This route was carved by the tributaries of the Price River on the eastern side of the mountains and the Spanish Fork River on the west. In addition, Thistle Creek provides a route south from Thistle towards the communities of the Sanpete and Sevier valleys.[9]:3 The Spanish Fork River flows northwest from Thistle, towards and through the city of Spanish Fork, before reaching Utah Lake.[8]

These natural paths have provided the route of several transcontinental trails, highways and railroads since their discovery. The named transportation arteries passing through Thistle include: US‑6 (originally numbered US‑50), US‑89, the Denver and Rio Grande Western Railroad's Utah Division (now part of Union Pacific Railroad's Central Corridor)[10][11] and D&RGW's Marysvale Branch line (abandoned because of the landslide).[12]


The trade route on which Thistle lies was used by Native American tribes before the arrival of European settlers; two Ute chiefs, Taby and Peteetneet, led seasonal migrations through the canyon each spring and fall.[9]:98 The first recorded journey by Europeans to modern Thistle was the Dominguez–Escalante Expedition, which was escorted through the territory by Indian guides.[13] A small group of Utes inhabiting the canyon frequently clashed with newcomers, and as a result were forcibly relocated in the 1870s.[9]:3

Historical population
Census Pop.
Source: U.S. Census Bureau[14]

Most of Thistle's residents were railroad employees sent to live in the town, but there were some who had settled before the railroads arrived. The first Europeans were part of the Mormon migration to Utah, and the first of these was the Pace family, who migrated from Nauvoo, Illinois, reaching Thistle in 1848. Fifth-generation descendants of the Pace settlers continued to operate a family-owned cattle ranch until the town was evacuated.[9]:99 Other settlers included Mormons who originally settled elsewhere in Utah but subsequently arrived to homestead fertile ground on Billies Mountain, on the north wall of the canyon. Among them was the mountain's presumed namesake, William Johnson. Homesteading was practiced in Thistle until the early 1900s. Until the arrival of the railroads, the town's economy was based mainly on farming and ranching, although there was also some mining activity in the region, including a vein of asphaltum that was mined between 1892 and 1914.[9]:94 & 118


The first railroad track laid through Thistle was a narrow-gauge spur line servicing coal mines near today's Scofield Reservoir, built in 1878 by the Utah and Pleasant Valley Railway. By 1890, the Denver and Rio Grande Western, which acquired the line in a foreclosure sale in 1882,[9]:5 had rebuilt the line to standard gauge. The D&RGW connected this line with one they had built west from Colorado, completing a link from Salt Lake City to Denver.[15]:157

The railroad built several facilities in Thistle to service and prepare trains for the change in grade and curvature of the line. The railroad placed helper engines on eastbound trains at Thistle for the ascent to Soldier Summit. The town provided a meal service for the trains until the use of on-board dining cars eliminated the need for meal stops.[15]:157

Aerial photo of the Thistle area in spring 1983 showing the dam formed by the landslide, "Lake Thistle" over the submerged town, and the construction to re-route US‑6, US‑89, and the D&RGW around the landslide area

Thistle saw more rail traffic with the construction of the Marysvale Branch line. This line branched from the main at Thistle, following modern US‑89 towards mines near Marysvale. Another line through Thistle, paralleling the D&RGW main, was built by the Utah Railway. The two lines were later combined into a dual-track main line, as part of a trackage rights agreement between the two companies.[15]:158

Rail traffic through Thistle continued to increase as the Rio Grande cooperated with connecting railroads, making the rail line through Thistle a bridge line for transcontinental rail traffic. The growth of Thistle was closely tied to the success of the Denver and Rio Grande Railroad throughout the era of steam locomotives.[12]

At its peak, around 1917, Thistle had about 600 residents. The town's railroad infrastructure included a five-stall roundhouse, depot, machine shop, and structures to restock passing trains with sand, coal and water. Non-railroad infrastructure included general stores, a post office, barber shop, saloon, pool hall, bakeries and restaurants. The largest building was a two-story schoolhouse, built in 1911.[9]:93

In the 1950s, the Denver & Rio Grande Western began to phase out steam locomotives in favor of diesel locomotives, which require less maintenance. With the change in technology, Thistle faded in importance.[15]:158 Gradually the town shrank in population; the passenger depot was torn down in 1972 and the post office closed in 1974. By 1983, only a few families remained in Thistle.[12]


A view from the California Zephyr, after the slide, showing the dam formed by the landslide and the scar from where the dirt slid, August 2003

Rio Grande maintenance personnel began noticing unstable ground downstream from Thistle years before the landslide occurred. Maintenance crews repaired the track on several occasions, but they did not fully investigate the problem.[15]:158 Beginning with the remnants of Hurricane Olivia, the autumn and winter of 1982–83 featured record-breaking snow and rainfall. As the spring thaw melted the winter snow, the mountains in the area became saturated with water.[9]:13-15

By April 1983, track deformation was a serious issue. On April 13, the division track master flew to Denver to explain the situation at a specially-called staff meeting. On the same day, a Utah Highway Patrol officer struck a newly created buckle in the highway that threw him against the roof of his vehicle. By the end of the day, a full maintenance crew was struggling to keep US‑6/US‑89 open. All trains were limited to speeds less than 10 miles per hour (16 km/h), and were accompanied by maintenance personnel who had to continually work to keep the tracks in line. The last train to pass through downtown Thistle was the westbound Rio Grande Zephyr, on April 14, 1983 at about 8:30 p.m. That night, both US‑6/US‑89 and the rail line were closed. One westbound freight train that had already left Denver was turned back. All through trains between Denver and Salt Lake City were rerouted to Union Pacific Railroad's Overland Route through Wyoming. By April 16, the tracks were completely buried and a voluntary evacuation order was issued for the town.[15]:159 [9]:17-19

Spanish Fork Canyon-Thistle view area
Looking northwest from the view area along US‑6/US‑89 showing the abandoned railroad and highway grades next to the replacement alignments, June 2010

On April 17, a final attempt to keep the landslide from blocking the flow of the river failed. That day, the Utah Department of Transportation and the Rio Grande announced plans to abandon the existing transportation arteries and build new corridors. Both the highway and railroad would be re-routed by blasting a path scaling the north wall of Spanish Fork Canyon. The new arteries would pass the slide by dynamiting through Billies Mountain, also along the north canyon wall. Engineers estimated the dam created by the toe of the landslide would eventually reach 200 to 300 feet (60 to 90 m) tall. The evacuation order was changed from voluntary to mandatory. Volunteers transported as many people and belongings as possible to the small town of Birdseye, about five miles (8 km) south. Most residents were able to recover only a fraction of their belongings; some had less than two hours' notice before the water reached their house.[9]:23 Thistle's oldest resident celebrated her 90th birthday at the evacuation center in Birdseye.[9]:123 By the 18th, the waterline had reached the rooftops of the 22 previously occupied houses. By the 19th, an entire mountain was moving at about two feet (0.6 m) per hour, and US‑6/US‑89 was buried by 50 feet (15 m) of soil.[16]

Spanish Fork River tunnel intake, Jul 15
The intake for the tunnel which rerouted the Spanish Fork River past the dam formed by the Thistle landslide, July 2015

Governor Scott Matheson requested federal aid to deal with the situation. After a visit to the area by the director of the Federal Emergency Management Agency, U.S. president Ronald Reagan issued the first presidential disaster area declaration for the state of Utah.[5] The landslide eventually formed a dam that created a lake three miles (5 km) long and over 200 ft (60 m) deep.[7] Concerned the dam could fail, the state of Utah decided to build a tunnel to re-route the flow of the Spanish Fork River.[12] The residents of downstream Spanish Fork were told to be prepared to evacuate. Engineers estimated that if the dam failed, they would have 30 to 45 minutes notice before the water reached the city.[16]


Buried house, Thistle, Utah
One of the few houses at Thistle to survive the landslide, April 2008

Thistle was almost completely destroyed. Most wooden buildings were carried away in the floodwaters. The state installed a temporary pumping station to prevent the lake from overflowing the dam; patrol boats skimmed up the floating remains of the town to prevent the debris from blocking the pumps. Most remains were either naturally deposited or placed on the eastern shore of the lake.[9]:52

By autumn, the tunnels to restore the flow of the river and drain the lake were operational. Shortly after, debates between former residents, neighboring residents, and government agencies began on what to do with the dam created by the landslide; some wanted to make the lake permanent. The state engineer commissioned a study to determine if the landslide dam could be used to retain water; it recommended building a new dam upstream from the landslide, rather than attempting engineering work on the landslide dam.[17]

In the years following, the former residents of Thistle filed various lawsuits to recover their losses. In one, they claimed that their property was taken to rebuild the road and railroad without just compensation.[18] Another lawsuit claimed negligence on the part of the D&RGW. The residents argued that the railroad's maintenance workers knew the ground was unstable; however, they only repaired the track. The residents contended the slide could have been prevented by using a water drainage system to relieve pressure at the head of the unstable area. They further contended that such a system could have been put in place had the railroad thoroughly investigated the problem upon first noticing it. The engineering firm employed by the Rio Grande said that their studies indicated the crown of the landslide was about 300 feet (90 m) above the level of the tracks, and that the Rio Grande did not know the true size of the unstable area until the slide was in motion. A jury absolved the D&RGW of responsibility.[19][20] The plaintiffs appealed the decision, and a second trial in 1993 resulted in a $1.1 million award for the landowners (equivalent to $2 million in 2019).[21] The D&RGW filed suit against the Utah Railway over sharing the costs from the landslide. The Utah Railway had an ownership interest in the line, based on a track-sharing agreement.[9]:73-75

Economic effects

Thistle 2010 from US6 rest area
The Thistle landslide, as seen from a view area along US‑6/US‑89, June 2010

The landslide closed the main railroad for three months, and US‑6 and US‑89 for eight months, during which time transportation between the communities of eastern and southeastern Utah and the rest of the state was substantially impaired. Security for the isolated part of Utah County was temporarily assigned to the Utah Highway Patrol.[22]

The economic effects of the closure of these transportation arteries were felt throughout the western United States; the closure devastated rural Utah. The operations of coal mines, uranium mines, turkey farms, animal feed companies, gypsum mines, and cement and clay factories were severely impacted. At least two trucking firms and one oil-producing firm suspended or ceased operations. Southeastern Utah's tourism industry suffered without access for visitors from the north and west. Some people who lived and worked on opposite sides of the landslide area suddenly had commutes exceeding 100 miles (160 km).[12][23] The highway patrol temporarily closed a weigh station at Peerless (a location along the US‑6 corridor near Helper) and built a temporary weigh station near Salina (along I‑70 about 90 miles (140 km) south of Thistle), which saw a sudden increase in truck traffic. The highway patrol estimated the temporary facilities inspected 57,000 trucks and made 80 arrests.[22]

The direct cost of the landslide was estimated at $200 million (equivalent to $503 million in 2019). However, some estimates of the total cost reached as high as $400 million (equivalent to $1006 million in 2019).[23][24] The D&RGW estimated the slide cost them $80 million in lost revenue (equivalent to $201 million in 2019), averaging $1 million for each day that the tracks were out-of-service. This figure included $19 million in payments to the Union Pacific for the use of their lines.[12] The United States Geological Survey and the state of Utah have called the Thistle landslide the most costly ever in the United States.[5][6]


East end of rail tunnels in Thistle, Utah, Jul 15
East end of Union Pacific Railroad's tunnels that bypassed the landslide in Thistle, July 2015

To expedite construction, the railroad had crews in Utah focused on grading the new path and boring a 3,000-foot (910 m) tunnel, while crews in Colorado built track segments that were transported to site. On July 4, 1983, at 3:05 p.m., safety inspectors declared the line ready for operation. At 3:12 p.m., the centralized traffic control signals gave a green light to the first train to pass through the Thistle area since the slide began, an eastbound freight train coming from the Southern Pacific Railroad at Ogden, destined for Herington, Kansas. Although the line's re-opening on Independence Day was coincidental, the first train became part of the local holiday celebrations. The first passenger train to use the new alignment was the California Zephyr, on July 16.[9]:73

Debates ensued over the fate of the Marysvale Branch line. The mines at the end of the line had long closed; the last train to traverse the entire length of the line passed through in 1970. Still, farmers and industry in the Sevier and Sanpete Valleys generated enough traffic that the line broke even most years. However, this line was severely damaged, with several washed-out bridges and railroad tracks draping over the sides of newly created cliffs. The railroad determined that at best it would take years to recover the cost of rebuilding the line.[15]:161

Thistle landslide
Map of Utah County showing the pre- and post-landslide alignments of US‑6, US‑89, and the area railroads

The residents of Richfield pressured the Rio Grande to use the portion of the line that was still intact and build a connection to an existing Union Pacific line (the Sharp Subdivision) near Nephi, roughly parallel to State Route 28. However, the railroad determined with the additional cost of acquiring land for the new right-of-way, the cost would be comparable to rebuilding the old route. In addition, the Rio Grande would have to pay trackage rights to the Union Pacific for the connection from Nephi, which would further erode profits on a line that was barely profitable. In the end, the Rio Grande sold the line to a scrap dealer who dismantled it.[15]:161 Since the line's closure, there have been multiple proposals to rebuild it. Studies note the loss of railroad access to the region has affected the ability of local industries to compete with producers in other regions that have rail access. A 2002 study placed the cost of rebuilding the modified routing of the Marysvale Branch line at $80 million,[24] while a 2015 study placed the cost of rebuilding the line as far south as Salina at $110 million (equivalent to $116 million in 2019). The 2015 study listed restoring rail access to the region as one of three priorities for new freight rail lines in a study presented by the Utah Department of Transportation detailing the current state of Utah's rail infrastructure. It specifically noted an increase of coal hauling trucks on highways and streets in the area due to the loss of rail access.[25]


The new alignment of US‑6/US‑89 was opened on December 30, 1983. The dedication was planned for the next day, but lines of cars formed at the barricades as soon as news broke that the highway was complete. Some were residents anxious to see the area or visit relatives they had not seen since the slide; others were truck drivers frustrated by long detours. The Highway Patrol requested the ceremony be canceled and the highway opened early, as they were unable to disperse the crowds.[26]

When the first traffic flowed, crews had not finished some final tasks, such as striping the roadway. Motorists saw a relocation with several mountain cuts built high up the canyon wall, with a view of the slide and former lake. The roadbed was not expected to last, as weather conditions had been unfavorable when the asphalt was laid. Two mountain cuts were unstable, requiring several months of work before they could be left unattended. During this time, the state stationed two full-time watches at the cuts, who would close the road while falling rocks were cleared. The cut through Billies Mountain was described by the construction crews as a new, man-made mountain pass.[26]

The pending completion of the again-rebuilt US‑6/US‑89, with properly laid asphalt and stable rock cuts, was announced in November 1984, 18 months after the closure of the original alignment.[26][27] Starting in 1993, the Utah Department of Transportation began discussions with former Thistle residents to build a memorial to the town.[28][29] The department maintains a view area overlooking the townsite along US‑6/US‑89.[30]

Coal Hollow fire

On August 4, 2018, a lightning bolt sparked a large fire in Spanish Fork Canyon.[31] More than 30,000 acres (47 sq mi; 120 km2) of land were destroyed by the fire.[32] Residents of the canyon were evacuated as a precaution. The fire affected Thistle, leading to the destruction of many of the remaining structures.

Geology and climate

The landslide area near Thistle is a valley formed in a depression in an area of bedrock known as the Charleston–Nebo thrust plate. The rock in this plate dates from the Permian and Pennsylvanian to the Jurassic periods, but the plate appears to have formed elsewhere and moved to the modern Thistle area during the Late Cretaceous epoch. The layers of sedimentary rock above the thrust plate are younger, dating to the Cretaceous and Tertiary periods.[17] The rock debris in the landslide itself comes from the North Horn and Ankareh formations.[5]

The area around Thistle has always been prone to landslides. Pre-historic landslides created the more gentle slopes that made the area usable as a transportation corridor across the Wasatch Mountains.[5][12] Minor landslides have been frequently observed, and continue to occur. The largest recorded landslides are the 1983 slide which destroyed the town, and a smaller one in 1998.[5]

The climate at downstream Spanish Fork is classified as arid with four distinct seasons.[33] Temperatures range from an average high of 92 °F (33 °C) in July and an average low of 20 °F (−7 °C) in January. Except for the spring months, precipitation averages less than 2 inches (5.1 cm) per month.[34]

See also


  1. ^ a b c d "Thistle". Geographic Names Information System. United States Geological Survey.
  2. ^ "Look Up a ZIP Code: ZIP Code by City and State". United States Postal Service. Retrieved March 19, 2018.
  3. ^ "Earthflow" (PDF). Institut de Physique du Globe de Paris. 2008. Retrieved November 15, 2014.
  4. ^ "Utah Landslide Hazards" (PDF). Public Information Series. Utah Geological Survey. 2011. Archived from the original (PDF) on August 27, 2013. Retrieved November 15, 2014.
  5. ^ a b c d e f g Milligan, Mark (May 2005). "Thistle Landslide Revisited, Utah County, Utah". Survey Notes. 37 (2). Retrieved October 28, 2009.
  6. ^ a b Schuster, Robert L.; Highland, Lynn M. (2001). "Open-File Report 01-0276: Socioeconomic and Environmental Impacts of Landslides in the Western Hemisphere". United States Geological Survey. Retrieved November 3, 2017.
  7. ^ a b Gore, Rick (June 1985). "The Rising Great Salt Lake–No Way to Run a Desert". National Geographic Magazine. 167 (6): 710.
  8. ^ a b Utah Road and Recreation Atlas (Map) (2002 ed.). 1:250000. Benchmark Maps. 2002. p. 51. § G12. ISBN 0-929591-74-7.
  9. ^ a b c d e f g h i j k l m n Sumsion, Oneita Burnside (1983). Thistle – Focus on Disaster. Springville, Utah: Art City Publishing Company. ISBN 978-0-936860-14-5.
  10. ^ "UPRR Common Line Names" (PDF) (Map). Union Pacific Railroad. Retrieved January 4, 2009.
  11. ^ "UP: Chronological History". uprr. Union Pacific Railroad. Archived from the original on March 5, 2014. Retrieved September 21, 2010.
  12. ^ a b c d e f g Atwood, Genevieve (1994), "Thistle", in Powell, Allan Kent (ed.), Utah History Encyclopedia, Salt Lake City: University of Utah Press, ISBN 978-0-87480-425-6, OCLC 30473917, archived from the original on October 10, 2013 – via Wayback Machine
  13. ^ Vélez de Escalante, Silvestre (1995). Warner, Ted J. (ed.). The Domínguez – Escalante Journal: Their Expedition Through Colorado, Utah, Arizona and New Mexico in 1776. Salt Lake City: University of Utah Press. p. 64. ISBN 978-0-87480-447-8.
  14. ^ "Census of Population and Housing". United States Census Bureau. Archived from the original on February 8, 2006. Retrieved March 10, 2010 – via Wayback Machine.
  15. ^ a b c d e f g h Carr, Stephen L.; Edwards, Robert W. (1989). Utah Ghost Rails. Salt Lake City: Western Epics. ISBN 978-0-914740-34-6.
  16. ^ a b Polly, Ron (April 19, 1983). "Thistle's way of life washed away". Deseret News. Salt Lake City.
  17. ^ a b Witkind, Irving J. (1986). "Potential Geologic Hazards Near the Thistle Landslide, Utah County, Utah". United States Geological Survey. Retrieved November 20, 2010.
  18. ^ "County seeks dismissal for Thistle residents' suit". Deseret News]]. Salt Lake City. May 13, 1987. p. B3. Retrieved March 10, 2010.
  19. ^ Rayburn, Ray (August 22, 1989). "Was Thistle Landslide Preventable". Deseret News. Salt Lake City. p. B4.
  20. ^ "D&RGW Wasn't at Fault in Thistle Slide, Jury Rules". Deseret News. August 30, 1989.
  21. ^ "Thistle landowners win suit against railroad". The Salt Lake Tribune. Salt Lake City. May 22, 1993. p. C3.
  22. ^ a b "1980–1989 Thistle Mud Slide". Utah Department of Public Safety. Archived from the original on February 23, 2012. Retrieved March 10, 2010 – via Wayback Machine.
  23. ^ a b Schuster, Robert L.; Highland, Lynn M. (2001). "Socioeconomic Impacts of Landslides in the Western Hemisphere". United States Geological Survey. Retrieved November 12, 2010.
  24. ^ a b Ashland, Francis X. (March 2003). "The Feasibility of Collecting Accurate Landslide-Loss Data in Utah" (PDF). Utah Geological Survey. p. 17. Retrieved March 19, 2018.
  25. ^ "Utah State Rail Plan" (PDF). Utah Department of Transportation. April 2015. pp. 138–140, 143, & 158. Retrieved March 18, 2018.
  26. ^ a b c Fackrell, Jerrie (January 1, 1984). "Eager travelers line up to cruise newly reopened road to Thistle". Deseret News. Salt Lake City – via Google News.
  27. ^ Fackrell, Jerrie (November 6, 1984). "Crews have nearly finished U.S. 6 over Billies Mountain". Deseret News. Salt Lake City – via Google News.
  28. ^ "Meeting Minutes – Utah Transportation Commission". Utah Department of Transportation. October 15, 1993. Retrieved April 6, 2010.
  29. ^ "Meeting Minutes – Utah Transportation Commission". Utah Department of Transportation. January 15, 1993. Retrieved April 6, 2010.
  30. ^ "Highway Reference Information [State Route 6]" (PDF). Utah Department of Transportation. August 16, 2017. p. 11. Retrieved March 19, 2018.
  31. ^ "Coal Hollow Fire closes U.S. 6 through Spanish Fork Canyon, forces evacuation of Diamond Fork Canyon". The Salt Lake Tribune. August 13, 2018. Retrieved September 26, 2018.
  32. ^ "Coal Hollow Fire information". InciWeb. September 21, 2018. Retrieved September 26, 2018.
  33. ^ "Spanish Fork – About the City". City of Spanish Fork. Archived from the original on September 7, 2010. Retrieved August 16, 2010.
  34. ^ "Monthly Averages for Spanish Fork, UT". The Weather Channel. Retrieved August 16, 2010.

External links

1977 Utah state route renumbering

In 1977, the Utah State Legislature changed its system of how state route numbers were used and assigned. Prior to 1977 Utah used a system where every U.S. Highway and Interstate Highway traversing the state was also assigned a different Utah state route number. This state route number was not posted on signs but was only used for legislative purposes, such as funding. There were many instances where having different route numbers for signing and legislative purposes could cause confusion. For example, the highway signed Interstate 15 in Utah was legislatively defined as State Route 1, not route 15. State Route 15 also existed, but was a different route that passed through Zion National Park.In 1977, the state changed to a system where all highways would have the same legislative route number as its signed route number. For example, Interstate 15 would also be route 15 for legislative purposes. Many state routes were re-numbered to eliminate instances where a state route used the same number as a U.S. Highway or Interstate Highway traversing the state. A smaller change was the creation of a new State Route 30 from combining other state routes.

In cases where 2 or more routes overlapped, only one of the route numbers sharing the same roadbed would be used in the legislative designation. The other routes in the overlap would have a discontinuity in the legislative description. For example, the stretch of highway between Green River and Crescent Junction is legislatively designated only Interstate 70. The other highways using this same pavement, U.S. Route 6, U.S. Route 50 and U.S. Route 191 all have legislative gaps in their routes for this portion.

Though the law was changed in 1977, most signs changed over in 1978.

40th parallel north

The 40th parallel north is a circle of latitude that is 40 degrees north of the Earth's equatorial plane. It crosses Europe, the Mediterranean Sea, Asia, the Pacific Ocean, North America, and the Atlantic Ocean.

At this latitude the sun is visible for 15 hours, 1 minute during the summer solstice and 9 hours, 20 minutes during the winter solstice. On 21 June, the maximum altitude of the sun is 73.83 degrees and 26.17 degrees on 21 December.

California Zephyr

The California Zephyr is a passenger train operated by Amtrak between Chicago and the San Francisco Bay Area (at Emeryville), via Omaha, Denver, Salt Lake City, and Reno. At 2,438 miles (3,924 km), it is Amtrak's second longest route after the Texas Eagle's triweekly continuation from San Antonio to Los Angeles, with travel time between the termini taking approximately 51​1⁄2 hours. Amtrak claims the route as one of its most scenic, with views of the upper Colorado River valley in the Rocky Mountains, and the Sierra Nevada. The modern train is the second iteration of a train named California Zephyr; the original train was privately operated and ran on a different route through Nevada and California.

During fiscal year 2018, the California Zephyr carried 418,203 passengers, an increase of 0.7% over FY2017. The train had a total revenue of $51,950,998 in FY2016, an increase of 6.5% over FY2015.

California Zephyr (1949–1970)

The California Zephyr was a passenger train that ran between Chicago, Illinois and Oakland, California via Omaha, Denver, Salt Lake City, Winnemucca, Oroville and Pleasanton. It was operated by the Chicago, Burlington & Quincy (CB&Q), Denver & Rio Grande Western (D&RGW) and Western Pacific (WP) railroads, all of which dubbed it "the most talked about train in America" on March 19, 1949, with the first departure the following day. The train was scheduled to pass through the most spectacular scenery on its route in the daylight. The original train ceased operation in 1970, though the D&RGW continued to operate its own passenger service, the Rio Grande Zephyr, between Salt Lake City and Denver, using the original equipment until 1983. In 1983 a second iteration of the California Zephyr, an Amtrak service, was formed. The current version of the California Zephyr operates partially over the route of the original Zephyr and partially over the route of its former rival, the City of San Francisco.

Landslides vs. Rock strength

Landslides are a major geologic hazard in many locations around the globe. They are considered a mass-wasting process, the most common of which are debris flows, hill slides, and rock falls. These events can take place over the course of several years of creeping but powerful movement, or in a matter of a few devastatingly destructive moments. There are several factors relating to structural geology that correlate directly to landslide occurrences. One major factor pertaining to landslides is rock strength. Rock strength is defined by stress/strain relationships, pore fluid pressure, and confining pressure. Stronger, more dense rocks are not as likely to be involved in a rock slide or landslide than porous less dense rocks that can be easily saturated with water. In Utah the groundwater level is continually fluctuating, making the area particularly susceptible to landslides. As water saturates the ground, making it softer and heavier, the stress/strain relationships experienced by the rocks increases considerably. The strength of a rock can be defined by its Mohr Circle, and its corresponding failure envelope. Once conditions are reached which place a rock over its failure envelope, it will experience deformation.

There are two main types of deformation which rocks undergo and both are pertinent to landslides. If a rock behaves elastically and experiences micro fractures involved with tiny slip movements in the rock, cohesive strength is still somewhat maintained, and a slide might be temporarily prevented. However, if a rock undergoes brittle deformation and breaks into pieces, a landslide is much more likely to occur. Stress and strain conditions associated with rocks and their failure envelopes differ between rock types, but they have been studied extensively in laboratories because the implications of these data have relevance in every scope of geology.

List of landslides

This list of landslides is a list of notable landslides and mudflows divided into sections by date and type. This list is very incomplete as there is no central catalogue for landslides, although some for individual countries/areas do exist. Volumes of landslides are recorded in the scientific literature using cubic kilometres (km3) for the largest and millions of cubic metres (normally given the non-standard shortening of MCM) for most events.

Rio Grande Zephyr

The Rio Grande Zephyr was a passenger train operated by Denver and Rio Grande Western Railroad (D&RGW or Rio Grande) between Denver, Colorado and Ogden, Utah from 1970 until 1983. In operation after the creation of publicly funded Amtrak, the Rio Grande Zephyr was the last privately operated intercity passenger train in the United States when it was discontinued. There have since been other privately operated trains in Florida.

San Francisco Zephyr

The San Francisco Zephyr was the name adopted in June 1972 for the Amtrak passenger train between Chicago, Illinois, and the San Francisco Bay Area in California. Previously, for those wanting to take a train between Chicago and Oakland, would have to take the City of San Francisco, which ran three times a week between Chicago and Oakland.

Because of the refusal of the Denver and Rio Grande Western Railroad to join Amtrak in 1971, and their decision to maintain their own train, the Rio Grande Zephyr, between Denver and Salt Lake City, once reaching Denver, the San Francisco Zephyr was required to head north, where it joined the Union Pacific's Overland Route, at a junction just west of Cheyenne, Wyoming, to continue through southern Wyoming, via Laramie, to Ogden, Utah. For passengers wanting to use the Rio Grande's service and continue on Amtrak, the timing of the trains was coordinated to facilitate a connection in Ogden (but not Denver) with the D&RGW's Rio Grande Zephyr. The San Francisco Zephyr traveled over rails operated by three different railroads: the Burlington Northern between Chicago and Denver, the Union Pacific between Denver and Ogden, and the Southern Pacific between Ogden and Oakland.

In July 1980, the San Francisco Zephyr was outfitted with Amtrak's new bi-level Superliner passenger cars, one of the last western trains to receive them. One of the results of this was that through service was introduced between Chicago and Seattle, as the Pioneer, and Los Angeles as the Desert Wind, with both the Pioneer and Desert Wind traveling with the Zephyr between Chicago and Ogden.

In 1983 the D&RGW chose to join Amtrak, citing increasing losses in passenger operations. Amtrak re-routed the San Francisco Zephyr over the D&RGW's line between Denver and Salt Lake City, Utah, which was its original preference in 1971. The change was scheduled for April 25, but a mudslide at Thistle, Utah, closed the D&RGW's main line and delayed the change until July 16. With the change of route Amtrak renamed the train California Zephyr.

Slump (geology)

A slump is a form of mass wasting that occurs when a coherent mass of loosely consolidated materials or rock layers moves a short distance down a slope. Movement is characterized by sliding along a concave-upward or planar surface. Causes of slumping include earthquake shocks, thorough wetting, freezing and thawing, undercutting, and loading of a slope.

Translational slumps occur when a detached landmass moves along a planar surface. Common planar surfaces of failure include joints or bedding planes, especially where a permeable layer overrides an impermeable surface. Block slumps are a type of translational slump in which one or more related block units move downslope as a relatively coherent mass.

Rotational slumps occur when a slump block, composed of sediment or rock, slides along a concave-upward slip surface with rotation about an axis parallel to the slope. Rotational movement causes the original surface of the block to become less steep, and the top of the slump is rotated backward. This results in internal deformation of the moving mass consisting chiefly of overturned folds called sheath folds.

Slumps have several characteristic features. The cut which forms as the landmass breaks away from the slope is called the scarp and is often cliff-like and concave. In rotational slumps, the main slump block often breaks into a series of secondary slumps and associated scarps to form stairstep pattern of displaced blocks. The upper surface of the blocks are rotated backwards, forming depressions which may accumulate water to create ponds or swampy areas. The surface of the detached mass often remains relatively undisturbed, especially at the top. However, hummocky ridges may form near the toe of the slump. Addition of water and loss of sediment cohesion at the toe may transform slumping material into an earthflow. Transverse cracks at the head scarp drain water, possibly killing vegetation. Transverse ridges, transverse cracks and radial cracks form in displaced material on the foot of the slump.

Slumps frequently form due to removal of a slope base, either from natural or manmade processes. Stream or wave erosion, as well as road construction are common instigators for slumping. It is the removal of the slope's physical support which provokes this mass wasting event. Thorough wetting is a common cause, which explains why slumping is often associated with heavy rainfall, storm events and earthflows. Rain provides lubrication for the material to slide, and increases the self-mass of the material. Both factors increase the rate of slumping. Earthquakes also trigger massive slumps, such as the fatal slumps of Turnagain Heights Subdivision in Anchorage, Alaska. This particular slump was initiated by a magnitude 8.4 earthquake that resulted in liquefaction of the soil. Around 75 houses were destroyed by the Turnagain Slump. Power lines, fences, roads, houses, and other manmade structures may be damaged if in the path of a slump.

The speed of slump varies widely, ranging from meters per second, to meters per year. Sudden slumps usually occur after earthquakes or heavy continuing rains, and can stabilize within a few hours. Most slumps develop over comparatively longer periods, taking months or years to reach stability. An example of a slow-moving slump is the Swift Creek Landslide, a deep-seated rotational slump located on Sumas Mountain, Washington.

Slumps may also occur underwater along the margins of continents and islands, resulting from tidal action or a large seismic event. These submarine slumps can generate disastrous tsunamis. The underwater terrain which encompasses the Hawaiian Islands gains its unusual hummocky topography from the many slumps that have taken place for millions of years.

One of the largest known slumps occurred on the south-eastern edge of the Agulhas Bank south of Africa in the Pliocene or more recently. This so-called Agulhas Slump is 750 km (470 mi) long, 106 km (66 mi) wide, and has a volume of 20,000 km3 (4,800 cu mi). It is a composite slump with proximal and distal allochthonous sediment masses separated by a large glide plane scar.

The Night Flyer (film)

The Night Flyer is a 1928 American silent drama film directed by Walter Lang. A print of the film exists in the film archive of the Library of Congress. Parts of the film were shot in Thistle, Utah.

U.S. Route 50

U.S. Route 50 or U.S. Highway 50 (US 50) is a major east–west route of the U.S. Highway system, stretching just over 3,000 miles (4,800 km) from Interstate 80 (I-80) in West Sacramento, California, to Maryland Route 528 (MD 528) in Ocean City, Maryland, on the Atlantic Ocean. Until 1972, when it was replaced by Interstate Highways west of the Sacramento area, it extended (by way of Stockton, the Altamont Pass, and the Bay Bridge) to San Francisco, near the Pacific Ocean. The Interstates were constructed later and are mostly separate from this route. It generally serves a corridor south of I-70 and I-80 and north of I-64 and I-40. The route runs through mostly rural desert and mountains in the western United States, with the section through Nevada known as "The Loneliest Road in America". In the Midwest, US 50 heads through mostly rural areas of farms as well as a few large cities including Kansas City, Missouri; St. Louis, Missouri; and Cincinnati, Ohio. The route continues into the eastern United States, where it passes through the Appalachian Mountains in West Virginia before heading through Washington, D.C. From there, US 50 continues through Maryland as a high-speed road to Ocean City. Signs at each end give the length as 3,073 miles (4,946 km), but the actual distance is slightly less, due to realignments since the former figure was measured. US 50 passes through a total of 12 states; California, Nevada, Utah, Colorado, Kansas, Missouri, Illinois, Indiana, Ohio, West Virginia, Virginia, and Maryland, as well as the District of Columbia.

US 50 was created in 1926 as part of the original U.S. Highway system. The original route planned in 1925 ran from Wadsworth, Nevada, east to Annapolis, Maryland, along several auto trails including the Lincoln Highway, Midland Trail, and the National Old Trails Road. The final 1926 plan had US 50 running from Sacramento, California, east to Annapolis with a gap in west Utah that was bridged by running the route north via Salt Lake City before rerouting it to US 6 in the 1950s. US 50 was extended west from Sacramento to San Francisco in the 1930s, replacing US 48; this was reversed in 1964 when I-580 replaced much of the route between the two cities. In addition, US 50 was extended east from Annapolis to Ocean City prior in 1949, replacing a portion of US 213. US 50 had two split configurations into US 50N and US 50S, one in Kansas and another in Ohio and West Virginia; both of these instances have been removed.

U.S. Route 50 in Nevada

U.S. Route 50 (US 50) is a transcontinental highway in the United States, stretching from West Sacramento, California, in the west to Ocean City, Maryland, on the east coast. The Nevada portion crosses the center of the state and was named The Loneliest Road in America by Life magazine in July 1986. The name was intended as a pejorative, but Nevada officials seized it as a marketing slogan. The name originates from large desolate areas traversed by the route, with few or no signs of civilization. The highway crosses several large desert valleys separated by numerous mountain ranges towering over the valley floors, in what is known as the Basin and Range province of the Great Basin.

US 50 has a diverse route through the state, traversing the resort communities of Lake Tahoe, the state capital in Carson City, historical sites such as Fort Churchill State Historic Park, petroglyphs, alpine forests, desert valleys, ghost towns, and Great Basin National Park.

The route was constructed over a historic corridor, initially used for the Pony Express and Central Overland Route and later for the Lincoln Highway. Before the formation of the U.S. Highway System, most of US 50 in Nevada was designated State Route 2. The routing east of Ely has changed significantly from the original plans. The route change resulted from a rivalry between Nevada and Utah over which transcontinental route was better to serve California-bound traffic, the Lincoln Highway or the Victory Highway.

U.S. Route 6

U.S. Route 6 (US 6), also called the Grand Army of the Republic Highway, honoring the American Civil War veterans association, is a main route of the U.S. Highway system. While it currently runs east-northeast from Bishop, California to Provincetown, Massachusetts, the route has been modified several times. The highway's longest-lasting routing, from 1936 to 1964, had its western terminus at Long Beach, California. During this time, US 6 was the longest highway in the country.

In 1964, the state of California renumbered its highways, and most of the route within California was transferred to other highways. This dropped the highway's length below that of US 20.

US 6 is a diagonal route, whose number is out of sequence with the rest of the U.S. Highway grid in the western US. When it was designated in 1926, US 6 only ran east of Erie, Pennsylvania. Subsequent extensions, largely replacing the former U.S. Route 32 (US 32) and U.S. Route 38 (US 38), have taken it south of US 30 near Chicago, Illinois, US 40 near Denver, Colorado (past the end of US 38), US 50 at Ely, Nevada, and even US 70 near Los Angeles, California, due to its north–south alignment in that state.

US 6 does not serve a major transcontinental corridor, unlike other highways. George R. Stewart, author of U.S. 40: Cross Section of the United States of America, initially considered US 6, but realized that "Route 6 runs uncertainly from nowhere to nowhere, scarcely to be followed from one end to the other, except by some devoted eccentric". In the famous "beat" novel On the Road by Jack Kerouac, protagonist Sal Paradise actually considers hitchhiking on US 6 to Nevada, but is told by a driver that "there's no traffic passes through 6" and that he'd be better off going via Pittsburgh (the Pennsylvania Turnpike).

U.S. Route 89

U.S. Route 89 (US 89) is a north–south United States Highway with two sections, and one former section. The southern section runs for 848 miles (1,365 kilometers) from Flagstaff, Arizona, to the southern entrance of Yellowstone National Park. The northern section runs for 404 miles (650 kilometers) from the northern entrance of Yellowstone National Park in Montana, ending at the Canada–US border. Unnumbered roads through Yellowstone connect the two sections. Before 1992, U.S. Highway 89 was a Canada to Mexico, border-to-border, highway that ended at Nogales, Arizona, on its southern end.Sometimes called the National Park Highway, U.S. 89 links seven national parks across the Mountain West. In addition, fourteen other national park areas, mostly national monuments, are also reachable from this backbone of the Rockies.

National Geographic named U.S. Route 89 the No. 1 Driver's Drive in the world.

U.S. Route 89 in Utah

U.S. Route 89 (US 89) in the U.S. state of Utah is a north–south United States Highway spanning more than 502 miles (807.891 km) through the central part of the state. Between Provo and Brigham City, US-89 serves as a local road, paralleling (and occasionally concurring with) Interstate 15, but the portions from Arizona north to Provo and Brigham City northeast to Wyoming serve separate corridors. The former provides access to several national parks and Arizona, and the latter connects I-15 with Logan, the state's only Metropolitan Statistical Area not on the Interstate.When US-89 was established in the state in 1926, the road initially extended north to US-91 in Spanish Fork. Following the extension of the former to the Canada–US border, Interstate 15 was constructed roughly paralleling US-89 to the west and replacing US-91 south of Brigham City. During this process, US-89 was rerouted in southern Utah and northern Arizona with the old roadway becoming US-89A.

Municipalities and communities of Utah County, Utah, United States
Ghost towns


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