In hydrology, snowmelt is surface runoff produced from melting snow. It can also be used to describe the period or season during which such runoff is produced. Water produced by snowmelt is an important part of the annual water cycle in many parts of the world, in some cases contributing high fractions of the annual runoff in a watershed. Predicting snowmelt runoff from a drainage basin may be a part of designing water control projects. Rapid snowmelt can cause flooding. If the snowmelt is then frozen, very dangerous conditions and accidents can occur, introducing the need for salt to melt the ice.
There are several energy fluxes involved in the melting of snow. These fluxes can act in opposing directions, that is either delivering heat to or removing heat from the snowpack. Ground heat flux is the energy delivered to the snowpack from the soil below by conduction. Radiation inputs to the snowpack include net shortwave (solar radiation including visible and ultraviolet light) and longwave (infrared) radiation. Net shortwave radiation is the difference in energy received from the sun and that reflected by the snowpack because of the snowpack albedo. Longwave radiation is received by the snowpack from many sources, including ozone, carbon dioxide, and water vapor present in all levels of the atmosphere. Longwave radiation is also emitted by the snowpack in the form near-Black-body radiation, where snow has an emissivity between 0.97 and 1.0. Generally the net longwave radiation term is negative, meaning a net loss of energy from the snowpack. Latent temperature flux is the energy removed from or delivered to the snowpack which accompanies the mass transfers of evaporation, sublimation, or condensation. Sensible heat flux is the heat flux due to convection between the air and snowpack.
Tree trunks absorbing sunlight become warmer than the air and cause earlier melting of snow around them. The snow does not melt slower gradually with distance from the trunk, but creates a wall surrounding snow-free ground around it rather. According to some of sources, North American spring ephermal plants like spring beauty (Claytonia caroliniana), trout lily (Erythronium americanum) and red trillium (Trillium erectum L.) benefit from such thaw circle. They can emerge earlier inside these circles, what gives them more time before development of tree canopy foliage cutting off significant portion of the light. They perform nearly all or nearly all of their yearly photosynthesis during this period.
The snow melts earlier in forest also for example on microtopographic mounds (small elevations) or in wet places like edges of creeks or in seeps. These microsites affect distribution of many herbs too.
In northern Alaska, the melt-date has advanced by 8 days since the mid-1960s. Decreased snowfall in winter followed by warmer spring conditions seems to be the cause for the advance. In Europe, the 2012 heat wave has especially been anomalous at higher altitudes. For the first time on record, some of the highest Alpine peaks in Europe were snow-free. Although it would seem that the two were related, the question of how much of this is due to climate change firmly remains a center of debate.
Increased water runoff due to snowmelt was a cause of many famous floods. One well-known example is the Red River Flood of 1997, when the Red River of the North in the Red River Valley of the United States and Canada flooded. Flooding in the Red River Valley is augmented by the fact that the river flows north through Winnipeg, Manitoba and into Lake Winnipeg. As snow in Minnesota, North Dakota, and South Dakota begins to melt and flow into the Red River, the presence of downstream ice can act as a dam and force upstream water to rise. Colder temperatures downstream can also potentially lead to freezing of water as it flows north, thus augmenting the ice dam problem. Some areas in British Columbia are also prone to snowmelt flooding as well.
The date of annual melt is of great interest as a potential indicator of climate change. In order to determine whether the earlier disappearance of spring snow cover in northern Alaska is related to global warming versus an appearance of a more natural, continual cycle of the climate, further study and monitoring is necessary.
Large year-to-year variability complicates the picture and furthers the debate. Inter-annual variability of springtime snow pack comes largely from variability of winter month precipitation which is in turn related to the variability of key patterns of atmospheric circulation.
A study of the mountains in the western United States show a region wide decline in spring snow-pack since the mid-1900s, dominated by loss at low elevations where winter temperatures are near freezing. These losses are an indication of increased temperatures which lead to snow loss via some combination of increased regularity of rain versus snow and increased melting during winter months. These natural variations make it challenging to quantify trends with confidence, to deduce observed changes to predict future climate, or to clearly detect changes in snow-pack due to human impact on warming trends.
Alpine plants are plants that grow in an alpine climate, which occurs at high elevation and above the tree line. There are many different plant species and taxon that grow as a plant community in these alpine tundra. These include perennial grasses, sedges, forbs, cushion plants, mosses, and lichens. Alpine plants are adapted to the harsh conditions of the alpine environment, which include low temperatures, dryness, ultraviolet radiation, and a short growing season.
Some alpine plants serve as medicinal plants.Bighorn National Forest
The Bighorn National Forest is a U.S. National Forest located in northern Wyoming, United States and consists of over 1.1 million acres (4,500 km²). Created as a US Forest Reserve in 1897, it is one of the oldest government-protected forest lands in the U.S. The forest is well east of the continental divide and extends from the Montana border for a distance of 80 miles (130 km) along the spine of the Bighorn Mountains, an outlying mountain range separated from the rest of the Rocky Mountains by Bighorn Basin. Elevations range from 5,000 feet (1,500 m) along the sagebrush and grass-covered lowlands at the foot of the mountains, to 13,189 feet (4,020 m) on top of Cloud Peak, the highest point in the Bighorn Mountains. Around 99% of the land is above 1,500 metres (4,900 ft). The forest is named after the Bighorn River, which is partially fed by streams found in the forest. Streams in the range are fed primarily by snowmelt and snowmelt mixed with driving rainfall.Within the forest is the Cloud Peak Wilderness area in which no motorized or mechanical equipment is allowed. The only access into the 189,000 acre (765 km²) wilderness is on foot or horseback. There are 1,500 miles (2,400 km) of trails in the forest, along with 32 improved campgrounds, lodges, and three scenic vehicular byways. U.S. Route 14 in Wyoming, also known as the Bighorn Scenic Byway, crosses the middle of the 30-mile (48 km) wide forest. The Medicine Wheel Passage (U.S. Highway 14A) crosses in the north passing the Medicine Wheel National Historic Landmark, while the Cloud Peak Skyway (U.S. Route 16) crosses the highest pass in the forest (Powder River Pass 9,677 ft/ 2,950 m) and is located in the southern section of the forest.
The forest headquarters is located in Sheridan, Wyoming. There are local ranger district offices in Buffalo, Lovell, and Sheridan. Visitor centers are located at Burgess Junction and near Shell Falls.Drainage basin
A drainage basin is any area of land where precipitation collects and drains off into a common outlet, such as into a river, bay, or other body of water. The drainage basin includes all the surface water from rain runoff, snowmelt, and nearby streams that run downslope towards the shared outlet, as well as the groundwater underneath the earth's surface. Drainage basins connect into other drainage basins at lower elevations in a hierarchical pattern, with smaller sub-drainage basins, which in turn drain into another common outlet.Other terms used interchangeably with drainage basin are catchment area, catchment basin, drainage area, river basin, water basin, and impluvium. In North America, the term watershed is commonly used to mean a drainage basin, though in other English-speaking countries, it is used only in its original sense, that of a drainage divide.
In a closed drainage basin, or endorheic basin, the water converges to a single point inside the basin, known as a sink, which may be a permanent lake, a dry lake, or a point where surface water is lost underground.The drainage basin acts as a funnel by collecting all the water within the area covered by the basin and channelling it to a single point. Each drainage basin is separated topographically from adjacent basins by a perimeter, the drainage divide, making up a succession of higher geographical features (such as a ridge, hill or mountains) forming a barrier.
Drainage basins are similar but not identical to hydrologic units, which are drainage areas delineated so as to nest into a multi-level hierarchical drainage system. Hydrologic units are defined to allow multiple inlets, outlets, or sinks. In a strict sense, all drainage basins are hydrologic units but not all hydrologic units are drainage basins.Freestone stream
In Fly fishing, a freestone stream flows seasonally, based on the water supply. In the summer and fall, freestone streams grow warm and have reduced flow because water from snow melt is less readily available. In contrast to limestone streams, which flow over limestone and dolomite, freestone streams generally flow over sandstone, shale, and crystalline rocks. Additionally, freestone streams are supplied by runoff and snowmelt, while limestone streams are usually fed by springs, providing cooler waters and a more stable pH balance.Freshet
The term freshet is most commonly used to describe a spring thaw resulting from snow and ice melt in rivers located in the upper North America. A spring freshet can sometimes last several weeks on large river systems, resulting in significant inundation of flood plains as the snowpack melts in the river's watershed. Freshets can occur with differing strength and duration depending upon the depth of the snowpack and the local average rates of warming temperatures. Deeper snowpacks which melt quickly can result in more severe flooding. Late spring melts allow for faster flooding; this is because the relatively longer days and higher solar angle allow for average melting temperatures to be reached quickly, causing snow to melt rapidly. Snowpacks at higher altitudes and in mountainous areas remain cold and tend to melt over a longer period of time and thus do not contribute to major flooding. Serious flooding from southern freshets are more often related to rain storms of large tropical weather systems rolling in from the South Atlantic or Gulf of Mexico, to add their powerful heating capacity to lesser snow packs. Tropically induced rainfall influenced quick melts can also affect snow cover to latitudes as far north as southern Canada, so long as the generally colder air mass is not blocking northward movement of low pressure systems.
In the eastern part of the continent, annual freshets occur from the Canadian Taiga ranging along both sides of the Great Lakes then down through the heavily forested Appalachian mountain chain and St. Lawrence valley from Northern Maine into barrier ranges in North Carolina and Tennessee.
In the western part of the continent, freshets occur throughout the generally much higher elevations of the various west coast mountain ranges that extend southward down from Alaska even into the northern parts of Arizona and New Mexico.
The term can also refer to the following:A flood resulting from heavy rain or a spring thaw. Whereas heavy rain often causes a flash flood, a spring thaw event is generally a more incremental process, depending upon local climate and topography.
A stream, river or flood of fresh water which empties into the ocean, usually flowing through an estuary.
A small stream of fresh water, irrespective of its outflow.
A pool of fresh water, according to Samuel Johnson and followed in Thomas Sheridan's dictionary, but this might have been a misinterpretation on Johnson's part, and it is at best not a common usage.Gallatin River
The Gallatin River is a tributary of the Missouri River, approximately 120 mi (193 km long), in the U.S. states of Wyoming and Montana. It is one of three rivers, along with the Jefferson and Madison, that converge near Three Forks, Montana, to form the Missouri.
It rises in the northwest corner of Yellowstone National Park, in northwestern Wyoming, in the Gallatin Range of the Rocky Mountains. It flows northwest through Gallatin National Forest, past Big Sky, Montana, and joins the Jefferson and Madison approximately 30 mi (48 km) northwest of Bozeman.
U.S. Highway 191 follows the river from the Wyoming border to just outside Bozeman.
The river was named in July 1805 by Meriwether Lewis at Three Forks. The eastern fork of the three, it was named for Albert Gallatin, the U.S. Treasury Secretary from 1801–14. The western fork was named for President Thomas Jefferson and the central fork for Secretary of State James Madison.
The Gallatin River is one of the best whitewater runs in the Yellowstone-Teton Area. In June, when the snowmelt is released from the mountains, the river has a class IV section called the "Mad Mile". This section is over a mile long and contains continuous stretches of challenging whitewater. Rafting companies offer trips on this river – on the Mad Mile Section as well as other, less challenging sections.
The Gallatin River is an amazingly scenic river – winding through high alpine meadows, dropping into the rocky Gallatin Canyon, and flowing out into the Gallatin Valley. It is an exceptionally popular fly fishing destination for rainbow trout, brown trout and mountain whitefish. Portions of the river are designated as a Blue Ribbon trout stream while the remainder is designated Red Ribbon by the Montana Fish, Wildlife and Parks Department. The river is closed to fishing from boats from Yellowstone Park to the confluence with the East Gallatin River. Parts of the movie A River Runs Through It were filmed on the Gallatin.
The river is a Class I water from Taylors fork to its confluence with the Missouri for the purposes of public access for recreational purposes.Glen Aulin High Sierra Camp
Glen Aulin High Sierra Camp is an established campground—one of six High Sierra Camps—located in Glen Aulin next to the Tuolumne River in Yosemite National Park in California, in the Sierra Nevada. The camp is located along the Tuolumne River at an elevation of approximately 7,800 feet (2,400 m). The High Sierra camps are only open during the summer months (snowmelt permitting - some years they do not open due to excessive snow) and reservations and National Park Service wilderness permits are required for their use.Hudson River-Black River Regulating District
The Hudson River-Black River Regulating District (HRBRRD) is a New York state public-benefit corporation that was established in 1922 in response to the severe historical flooding of the cities of Albany, Green Island, Rensselaer, Troy, and Watervliet by the Sacandaga River and Hudson River and its tributaries. The HRBRRD was created to collect excess runoff to prevent flooding in the Hudson River and Black River basins, and to release this captured water gradually during periods of low river flow to maintain water quality in each river basin. This system was designed to reduce damage from spring storms and snowmelt, including disease and destruction of life and property, and to improve river navigation and public sanitation. The HRBRRD was also formed with hydroelectric generation in mind. It owns and operates several dams - including the Conklingville Dam which formed the Great Sacandaga Lake - and reservoirs.Hydroscaphidae
The Hydroscaphidae are a small family of water beetles known commonly as skiff beetles. As of 2010, there are 23 species in the family. Several are recently described.
These beetles are small, most under 2 mm in length. They are tan to brown in color and the elytra are abbreviated, leaving several tapering tergites of the abdomen exposed. The wings are fringed with long setae. The larvae are fusiform, with a wide thorax and a narrowing abdomen.These beetles live on mats of algae with a thin layer of running water. This may be the accumulated algae lining the very edge of a stream of water. They tolerate a wide range of temperatures; they have been observed in hot springs and in icy snowmelt. The algae are their food source.The reproductive cycle is not well known. In at least one species, the female lays a single large egg on the algal mat.Hydroscaphid species have been reported from every continent except Antarctica.
YaraLake Wenatchee State Park
Lake Wenatchee State Park is a public recreation area located at the eastern end of Lake Wenatchee, a glacier- and snowmelt-fed lake in the Wenatchee National Forest on the eastern slopes of the Cascades Mountain Range in the state of Washington. The state park covers 492 acres (199 ha) split into two parts—the north shore park and the south shore park—separated by the Wenatchee River. The park is managed by the Washington State Parks and Recreation Commission.North Saskatchewan River flood of 1915
The North Saskatchewan River flood of 1915 was one of the largest floods in the history of Edmonton. On 28 June, the Edmonton Bulletin reported the river had risen "10 feet in as many hours." A frantic telegram from Rocky Mountain House alerted local authorities to the flood's arrival. The Canadian Northern Railway had parked a number of train cars on the city's Low Level Bridge to protect against the debris that had been pushed up against its piers, including a house swept away by the current. Thousands of Edmonton residents watched the flood destroy lumber mills along the city's river valley.Like all rivers, the North Saskatchewan River is subject to periodic flooding, beginning with rapid snowmelt in the mountains or prolonged periods of rain in the river basin. With the establishment of permanent communities along the river's course, and the rise of an administrative/government structure, records exist recording floods in the North Saskatchewan for the past century. The Bighorn Dam, constructed in the early 1970s near Nordegg, Alberta, and the Brazeau Reservoir, constructed in the mid-1960s, have not reduced potential for flooding on the North Saskatchewan River.Red River (New Mexico)
The Red River of New Mexico, USA, is a short, perennial river that flows down the north slope of Mount Wheeler in the Sangre de Cristo Mountains, flows west past the towns of Red River and Questa and then south into the Rio Grande just south of the La Junta Campground.
The Red River is Taos’s winter fishery with prime time being from October through early April. The Red provides visitors the unique opportunity to fish and ski on the same trip to Taos. A myriad of springs flow into the river greatly increasing the flows and keeping the water temperatures in the optimum trout fishing range of between 45 and 60 degrees making the Red an ideal winter trout fishery.
As the summer monsoon season comes to an end and afternoon showers begin to taper off, the river settles down and clears nicely, allowing the fun to begin.
In the fall, towards the middle to end of October, larger rainbow trout begin staging in the lower reaches of the river near the confluence with the Rio Grande and start pushing up the river to spawn, creating a great opportunity for a shot at some big Browns through November as they migrate up river and back again.
The Red River is noted for its trout fishery and its lower portion is part of the Wild Rivers Recreation Area. Located below Questa on the river is the New Mexico Red River Fish Hatchery.
The Red River derives its water from snowmelt and summer season convective storms and due to the relatively consistent patterns of orographic precipitation it is a perennial stream.Semliki River
Semliki River (sometimes Semuliki) is a major river, 140 kilometres (87 mi) long, in the Democratic Republic of the Congo (DRC) and Uganda in Central and East Africa. It flows north from Lake Edward to Lake Albert in the Albertine Rift west of the Rwenzori Mountains. Along its lower reaches, it forms part of the international border between the DRC and the western Ugandan district of Bundibugyo, near the Semuliki National Park. It empties into Lake Albert slightly west of the border in Orientale Province of the DRC.Increasing snowmelt from the Rwenzoris, overgrazing, and other alterations to the watershed have caused bank erosion and frequent changes to the course of the meandering lower reaches of the river. In some places, Uganda is losing up to 10 metres (33 ft) of land per year on its side of the river to erosion, and silt from the Semliki is gradually filling in the southern end of Lake Albert. In other places, it is the DRC that is losing territory as the changing river course alters the apparent location of the border.Sistan Basin
The Sistan Basin is an inland endorheic basin encompassing large parts of southwestern Afghanistan and minor parts of southeastern Iran, one of the driest regions in the world and an area subjected to prolonged droughts. Its watershed is a system of rivers flowing from the highlands of Afghanistan into freshwater lakes and marshes and then to its ultimate destination: Afghanistan's saline Godzareh depression, part of the extensive Sistan terminal basin. The Helmand River drains the basin's largest watershed, fed mainly by snowmelt from the mountains of Hindu Kush, but other rivers contribute also.A basalt hill, known as Mount Khajeh, rises beside the lakes and marshes of the basin.Snoqualmie River
The Snoqualmie River is a 45-mile (72 km) long river in King County and Snohomish County in the U.S. state of Washington. The river's three main tributaries are the North, Middle, and South Forks, which drain the west side of the Cascade Mountains near the town of North Bend and join near the town of Snoqualmie just above the Snoqualmie Falls. After the falls the river flows north through rich farmland and the towns of Fall City, Carnation, and Duvall before meeting the Skykomish River to form the Snohomish River near Monroe. The Snohomish River empties into Puget Sound at Everett. Other tributaries of the Snoqualmie River include the Taylor River and the Pratt River, both of which enter the Middle Fork, the Tolt River, which joins at Carnation, and the Raging River at Fall City.
Many of the Snoqualmie River's headwaters originate as snowmelt within the Alpine Lakes Wilderness. On August 8, 2007, U.S. Representative Dave Reichert (WA-08), King County Executive Ron Sims, and others announced a proposal to expand the Alpine Lakes Wilderness to include the valley of the Pratt River, a tributary of the Middle Fork, near the town of North Bend. The proposal would also give the Pratt River National Wild and Scenic River status.Snow
Snow refers to forms of ice crystals that precipitate from the atmosphere (usually from clouds) and undergo changes on the Earth's surface. It pertains to frozen crystalline water throughout its life cycle, starting when, under suitable conditions, the ice crystals form in the atmosphere, increase to millimeter size, precipitate and accumulate on surfaces, then metamorphose in place, and ultimately melt, slide or sublimate away. Snowstorms organize and develop by feeding on sources of atmospheric moisture and cold air. Snowflakes nucleate around particles in the atmosphere by attracting supercooled water droplets, which freeze in hexagonal-shaped crystals. Snowflakes take on a variety of shapes, basic among these are platelets, needles, columns and rime. As snow accumulates into a snowpack, it may blow into drifts. Over time, accumulated snow metamorphoses, by sintering, sublimation and freeze-thaw. Where the climate is cold enough for year-to-year accumulation, a glacier may form. Otherwise, snow typically melts seasonally, causing runoff into streams and rivers and recharging groundwater.
Major snow-prone areas include the polar regions, the upper half of the Northern Hemisphere and mountainous regions worldwide with sufficient moisture and cold temperatures. In the Southern Hemisphere, snow is confined primarily to mountainous areas, apart from Antarctica.Snow affects such human activities as transportation: creating the need for keeping roadways, wings, and windows clear; agriculture: providing water to crops and safeguarding livestock; sports such as skiing, snowboarding, and snowmachine travel; and warfare. Snow affects ecosystems, as well, by providing an insulating layer during winter under which plants and animals are able to survive the cold.Snowmelt system
A snowmelt system prevents the build-up of snow and ice on cycleways, walkways, patios and roadways, or more economically, only a portion of the area such as a pair of 2-foot (0.61 m)-wide tire tracks on a driveway or a 3-foot (0.91 m) center portion of a sidewalk, etc. They function even during a storm thus improve safety and eliminate winter maintenance labor including shoveling or plowing snow and spreading de-icing salt or traction grit (sand). A snowmelt system may extend the life of the concrete, asphalt or under pavers by eliminating the use salts or other de-icing chemicals, and physical damage from winter service vehicles.
Systems are available in two broad types based on heat source: electric resistance heat and heat from a combustion or geothermal source delivered hydronically (in a fluid). Arguably, electric snowmelt systems requires less maintenance than hydronic snowmelt systems because there are minimal moving parts and no corroding agents. However electric snowmelt systems tend to be much more expensive to operate.
Most new snowmelt systems operate in conjunction with an automatic activation device that will turn the system on when it senses precipitation and freezing temperatures and turn it off when temperatures are above freezing. These types of devices ensure the system is only active during useful periods and reduces energy waste. A high limit thermostat further increases efficiency when installed in conjunction with the automatic snow melt controller to temporarily disable the system once the slab has reached a sufficient snow melting temperature. Some building codes require the high limit thermostat to prevent energy waste. Total environmental impact depends on the energy source used.Street Mountain (New York)
Street Mountain is a mountain located in Essex County, New York, named after Alfred Billings Street (1811–1881), a poet and New York State Librarian.
The mountain is the high point of the Street Range of the Adirondack Mountains.
Street's northeast ridge is Nye Mountain.
Street Mountain stands within the watershed of the Saint Lawrence River, which drains into the Gulf of Saint Lawrence.
The southeast, east, and northeast slopes of Street Mtn. drain into the northern Indian Pass Brook, thence into the West Branch of the Ausable River, and Lake Champlain, thence into Canada's Richelieu River, and the Saint Lawrence River.
The north and northwest slopes of Street Mtn. drain into the headwaters of the Chubb River, thence into the Ausable's West Branch.
The west end of Street Mtn. drains into the northern Moose Creek, and thence into the Cold River, the Raquette River, and the Saint Lawrence River in Canada.
The southwest slopes of Street Mtn. drain into Roaring Brook, thence into Duck Hole pond, the source of the Cold River.
Street Mountain is within the High Peaks Wilderness Area of New York's Adirondack Park.
The trail to the peak is unmarked and can be disorienting if there is snow covering the footpath. One portion of the trail requires hikers to cross a stream and it can become uncrossable if raining (especially during Spring snowmelt). Hikers are advised to bring a map and compass.Økern (station)
Økern is a metro station on the No 5, Grorud Line of the Oslo Metro system, situated between stations Hasle and Risløkka in the lower parts of the Grorud Valley. It is located 2.7 km (the geodesic distance) northeast of station Stortinget (the Parliament). The station is part of the original stretch of the Grorud Line, and was opened on 16 October 1966. In 2010, the station was refurbished and partly rebuilt. New platforms are fitted with snowmelt systems.
The station is also located at the intersection of the metro line and the Ring 3 highway, which encircles most of the inner part of the city of Oslo.
The area around Økern is dominated by private enterprises, with the Økern Næringspark office park and the Økern shopping centre in the immediate vicinity.