A report on Snow

Norwegian train plowing through drifted snow
Extratropical cyclonic snowstorm, February 24, 2007—(Click for animation.)
Frontal snowsquall moving toward Boston, Massachusetts
Cold northwesterly wind over Lake Superior and Lake Michigan creating lake-effect snowfall
Freshly fallen snowflakes
An early classification of snowflakes by Israel Perkins Warren
An animation of seasonal snow changes, based on satellite imagery
New York City during a 2016 blizzard, which
 produced local wind gusts up to 42 mph and dropped 27.5 in of snow, breaking the city's one-day snowfall record.
Snow-covered trees in Kuusamo, Finland
Fresh snow beginning to metamorphose: The surface shows wind packing and sastrugi. In the foreground are hoar frost crystals, formed by refrozen water vapor emerging to the cold surface.
Firn—metamorphosed multi-year snow
Snow drifts forming around downwind obstructions
A powder snow avalanche
Snowmelt-induced flooding of the Red River of the North in 1997
Snow pit on the surface of a glacier, profiling snow properties where the snow becomes increasingly dense with depth as it metamorphoses towards ice
Snowfall and snowmelt are parts of the Earth's water cycle.
Traffic stranded in a 2011 Chicago snowstorm.
Winter conditions on Ontario Highway 401 in Toronto due to a snowsquall.
Deicing an aircraft during a snow event
Satellite view of the Indus River, showing snow in the Himalayas, which feeds it, and agricultural areas in Pakistan that draw on it for irrigation.
Extreme snow accumulation on building roofs
Icings resulting from meltwater at the bottom of the snow pack on the roof, flowing and refreezing at the eave as icicles and from leaking into the wall via an ice dam.
Alpine skiing.
Algae, Chlamydomonas nivalis, that thrive in snow form red areas in the suncups on this snow surface
Arctic fox, a predator of smaller animals that live beneath the snow
Trucks plowing snow on a highway in Missouri
Airport snow-clearing operations include plowing and brushing
Swiss low-profile, train-mounted snowplow
Bivouac of Napoleon's Grande Armée, during the winter retreat from Moscow
Finnish ski troops during the invasion of Finland by the Soviet Union
Army vehicles coping with snow during the Battle of the Bulge of World War II.
Norwegian military preparations during the 2009 Cold Response exercise
Navy SEALs training for winter warfare at Mammoth Mountain, California.
Worldwide occurrence of snowfall. Snow at reference above sea level (meters):Below 500: annually.
Below 500: annually, but not in all of its territory.
500: above annually, below occasionally.
Above 500: annually.
Above 2,000: annually.
Any elevation: none.

Snow comprises individual ice crystals that grow while suspended in the atmosphere—usually within clouds—and then fall, accumulating on the ground where they undergo further changes.

- Snow
Norwegian train plowing through drifted snow

31 related topics with Alpha

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Bentley at work

Wilson Bentley

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American meteorologist and photographer, who was the first known person to take detailed photographs of snowflakes and record their features.

American meteorologist and photographer, who was the first known person to take detailed photographs of snowflakes and record their features.

Bentley at work
Snowflake photos by Bentley, circa 1902
Bentley snowflake micrograph, 1890

He first became interested in snow crystals as a teenager on his family farm.

Névé in a valley of Haute-Savoie, France

Névé

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Névé in a valley of Haute-Savoie, France

Névé is a young, granular type of snow which has been partially melted, refrozen and compacted, yet precedes the form of ice.

Visibility reduced in blowing snow during a ground blizzard

Blowing snow

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Visibility reduced in blowing snow during a ground blizzard

Blowing snow is snow lifted from the surface by the wind, at eye level (1.8 m) or more, that will reduce visibility.

A powder snow avalanche in the Himalayas near Mount Everest.

Avalanche

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A powder snow avalanche in the Himalayas near Mount Everest.
Heavy equipment in action after an avalanche has interrupted service on the Saint-Gervais–Vallorcine railway in Haute-Savoie, France (2006).
The terminus of an avalanche in Alaska's Kenai Fjords.
Loose snow avalanches (far left) and slab avalanches (near center) near Mount Shuksan in the North Cascades mountains. Fracture propagation is relatively limited.
15 cm deep, soft slab avalanche triggered by a snowboarder near Heliotrope Ridge, Mount Baker in March 2010. Multiple crown fracture lines are visible in the top-middle of the image. Note the granular characteristic of the debris in the foreground that results from the slab breaking up during descent.
Avalanche on Simplon Pass (2019)
In steep avalanche-prone terrain, traveling on ridges is generally safer than traversing the slopes.
A cornice of snow about to fall. Cracks in the snow are visible in area (1). Area (3) fell soon after this picture was taken, leaving area (2) as the new edge.
Avalanche path with 800 m vertical fall in the Glacier Peak Wilderness, Washington state. Avalanche paths in alpine terrain may be poorly defined because of limited vegetation. Below tree line, avalanche paths are often delineated by vegetative trim lines created by past avalanches. The start zone is visible near the top of the image, the track is in the middle of the image and clearly denoted by vegetative trimlines, and the runout zone is shown at the bottom of the image. One possible timeline is as follows: an avalanche forms in the start zone near the ridge, and then descends the track, until coming to rest in the runout zone.
After surface hoarfrost becomes buried by later snowfall, the buried hoar layer can be a weak layer upon which upper layers can slide.
After digging a snow pit, it is possible to evaluate the snowpack for unstable layers. In this picture, snow from a weak layer has been easily scraped away by hand, leaving a horizontal line in the wall of the pit.
United States Forest Service avalanche danger advisories.
Snow fences in Switzerland during summer.
Avalanche blasting in French ski resort Tignes (3,600 m)
Avalanche warning sign near Banff, Alberta
Radar station for avalanche monitoring in Zermatt.
frameless

An avalanche is a rapid flow of snow down a slope, such as a hill or mountain.

Sampling the surface of a glacier. There is increasingly dense firn between surface snow and blue glacier ice.

Firn

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Sampling the surface of a glacier. There is increasingly dense firn between surface snow and blue glacier ice.
Firn field on the top of Säuleck, Hohe Tauern

Firn (from Swiss German firn "last year's", cognate with before) is partially compacted névé, a type of snow that has been left over from past seasons and has been recrystallized into a substance denser than névé.

Vintage ski waxes, once used by U.S. Army ski troops. Left to right are: grip waxes in canisters (blue for "dry snow" and yellow for "wet and corn snow") and a paraffin glide wax.

Ski wax

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Vintage ski waxes, once used by U.S. Army ski troops. Left to right are: grip waxes in canisters (blue for "dry snow" and yellow for "wet and corn snow") and a paraffin glide wax.
Swedish ski racer, Martin Matsbo, pioneered development of modern cross-country ski waxes.
Conceptual representation of sliding friction over snow, as a function of water film thickness, created by passage of a ski or other slider over a snow surface.
Canister of vintage German grip wax.
Soviet-era Visti (Висти)–brand klisters, graded by color and temperature range.
Dendritic snowflake—micrograph by Wilson Bentley.
Platelets and needles, two alternate forms of snowflakes.
Fresh, dry snow with newly formed bonds, showing a grain boundary (top center).
Cluster of ice grains in wet snow at a low liquid content—grain crystals range 0.5 to 1.0 mm.
Melting glide wax onto a skate ski to be ironed in and scraped smooth.
Application of grip wax to a classic cross-country ski, using a canister of wax, like those shown in the left foreground.
Smoothing of grip wax on a classic cross-country ski, using a hand-held "cork", like the item marked "Swix" in the right foreground.

Ski wax is a material applied to the bottom of snow runners, including skis, snowboards, and toboggans, to improve their coefficient of friction performance under varying snow conditions.

A snowmobile tour at Yellowstone National Park.

Snowmobile

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A snowmobile tour at Yellowstone National Park.
Harry Kalenze, inventor of the Vehicle Propeller
1921 Ford Model T snowmobile
Motor sled powered by a Coandă ducted fan
Snowmobile running on the Mississippi River near Hastings, Minnesota, 1910
Nicholas II Packard Twin-6 with Kégresse track
Early Bombardier Snowmobile
Early snowmobile interior
Airplane-engine-powered skimobile taxi in Red Lake, Canada, 1937
A snowmobile used by emergency services in ski areas in Vercors, French Alps. It carries emergency equipment and tows a stretcher.
Alpina Sherpa, a dual track snowmobile
Arctic snowmobile with heated cabin
A family with snowmobiles at the forest of Ruka in Kuusamo, Finland
Student-constructed SAE clean snowmobile at Imagine RIT 2017.
Snowmobiling near Martin Lake, Northwest Territories, Canada for a winter picnic in February.
Snowmobiles are used by reindeer herders
Snowmobile race
X-Games athlete Ethen Roberts posing with his snow bike

A snowmobile, also known as a Ski-Doo, snowmachine, sled, motor sled, motor sledge, skimobile, or snow scooter, is a motorized vehicle designed for winter travel and recreation on snow.

Dark green crystals of nickelocene, sublimed and freshly deposited on a cold finger

Sublimation (phase transition)

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Transition of a substance directly from the solid to the gas state, without passing through the liquid state.

Transition of a substance directly from the solid to the gas state, without passing through the liquid state.

Dark green crystals of nickelocene, sublimed and freshly deposited on a cold finger
Comparison of phase diagrams of carbon dioxide (red) and water (blue) showing the carbon dioxide sublimation point (middle-left) at 1 atmosphere. As dry ice is heated, it crosses this point along the bold horizontal line from the solid phase directly into the gaseous phase. Water, on the other hand, passes through a liquid phase at 1 atmosphere.
Dry ice subliming in air
Experimental set up for the sublimation reaction of naphthalene Solid naphthalene sublimes and form the crystal-like structure at the bottom of the watch glass
Solid compound of naphthalene sublimed to form a crystal-like structure on the cool surface.
Camphor subliming in a cold finger. The crude product in the bottom is dark brown; the white purified product on the bottom of the cold finger above is hard to see against the light background.
Crystals of ferrocene after purification by vacuum sublimation

Snow and ice sublime, although more slowly, at temperatures below the freezing/melting point temperature line at 0 °C for partial pressures below the triple point pressure of 612 Pa. In freeze-drying, the material to be dehydrated is frozen and its water is allowed to sublime under reduced pressure or vacuum.

Band of thunderstorms seen on a weather radar display

Rainband

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Cloud and precipitation structure associated with an area of rainfall which is significantly elongated.

Cloud and precipitation structure associated with an area of rainfall which is significantly elongated.

Band of thunderstorms seen on a weather radar display
A February 24, 2007 radar image of a large extratropical cyclonic storm system at its peak over the central United States. Note the band of thunderstorms along its trailing cold front.
Photograph of rainbands in Hurricane Isidore

Banding within the comma head precipitation pattern of an extratropical cyclone can yield significant amounts of rain or snow.

Shower in Reignier-Esery, Haute-Savoie, France.

Shower (precipitation)

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Mode of precipitation characterized by an abrupt start and end and by rapid variations in intensity.

Mode of precipitation characterized by an abrupt start and end and by rapid variations in intensity.

Shower in Reignier-Esery, Haute-Savoie, France.
Vertical motion of the air parcel with a given mixing ratio resulting into a convective cloud formation.
A violent electrical storm results from convective cumulonimbus above the LCL.

A shower will produce rain if the temperature is above the freezing point in the cloud, or snow / ice pellets / snow pellets / hail if the temperature is below it at some point.