Benefits and problems

Snow is used as a thermal insulator conserving the heat of the Earth and protecting crops from the freezing weather. On the other hand, substantial snowfall sometimes may even disrupt the infrastructure and services of a region that is accustomed to such weather. Automotive traffic may be greatly inhibited or may be stifled entirely. Basic infrastructures such as electricity, telephone lines, and gas supply can also be shut down. This can lead to a "snow day", which is a day on which the school or other services are cancelled due to unusually heavy snowfall.

Superlatives

The highest seasonally cumulative precipitation of snow ever measured was on Mount Baker, Washington in the United States during the 1998–1999 season. Mount Baker received 1140 in. (29 m) of snow [1], thus surpassing the previous record holder, Mount Rainier, Washington which during the 1971–1972 season received 1122 in. (28.5 m) of snow [2].

Geometry

A snowflake always has six symmetric arms (along three symmetric axes), which arises from the hexagonal crystal structure of ordinary ice (known as ice I_h) along its 'basal' plane.

Electron Microscope Gallery

Recreation

Some forms of recreation depend on snow

Density

The water equivalent of a snow pack is the amount of water that it contains, regardless of its depth. For example, if the snow covering a given area has a water equivalent of 5 m, then it will melt into a pool of water 5 m deep covering the same area. This is a much more useful measurement to hydrologists than snow depth, as the density of even freshly fallen snow widely varies. New snow often has a density of around 12% of water, and even under cold conditions, the same snow will settle under its own weight until it is approximately 33% water. More snow on top of this will compress it even further. By late spring, snow densities often exceed 50% of water [3].

Types

Ice

Densely, packed material formed from snow that doesn't contain air bubbles. Depending on the snow accumulation rate, the air temperature, and the weight of the snow in the upper layers, it can take snow a few hours or a few decades to form into ice.

Corn

Coarse, granular wet snow. Most commonly used by skiers describing good spring snow. Corn is the result of diurnal cycle of melting and refreezing.

Thundersnow

A thunderstorm which produces snow as the primary form of precipitation.

Powder

Freshly fallen, uncompacted snow. The density and moisture content of powder snow can vary widely; snowfall in coastal regions and areas with higher humidity is usually heavier than a similarly depth of snowfall in an arid or continental region. Light, dry (low moisture content) powder snow is prized by skiers and snowboarders. It is often found in the Rocky Mountains of North America.

Firn

Snow which has been lying for at least a year but which has not yet consolidated into glacier ice. It is granular.

Flurries

A period of light snow with usually little accumulation with occasional moderate snowfall.

Sleet

In Britain, rain mixed with snow; in America, ice pellets formed when snowflakes pass through a layer of warm air, thaw, then refreeze on further descent.

Soft hail

Granules of snow or ice pellets formed when supercooled water accretes on ice crystals or snowflakes.

Freezing rain

Rain that freezes on impact with a sufficiently cold surface. This can cover trees in a uniform layer of very clear, shiny ice, a beautiful phenomenon, though excessive accumulation can break tree limbs and utility lines, causing utility failures and possible property damage.

Snizzle

Extremely small snow/ice particles that fall lightly, almost like drizzle that is frozen. This kind of snow is very common in Michigan.^{[citation needed]} This termed was coined by a meteorologist in the Boston television station WBZ-TV.^{[citation needed]}

Snow storm

A long storm of relatively heavy snow.

Snow squall

A brief, very intense snowstorm.

Blizzard

A long-lasting snow storm with intense snowfall and usually high winds. Particularly severe storms can create whiteout conditions where visibility is reduced to less than 1 m.

Lake effect snow

Produced when cold winds move across long expanses of warmer lake water, picking up water vapor which freezes and is deposited on the lee shores.

Snowdrift

Large piles of snow which occur near walls and curbs, as the wind tends to push the snow up toward the vertical surfaces.

Ground blizzard

Occurs when a strong wind drives already fallen snow to create drifts and whiteouts.

Packing snow

Snow that is at or near the melting point, so that it can easily be packed into snowballs and hurled at other people or objects. This is perfect for snow fights and other winter fun, such as making a snowman, or a snow fort.

Slush

Snow which partially melts upon reaching the ground, to the point that it accumulates in puddles of partially-frozen water.

Hail

Many-layered ice balls, ranging from "pea" sized (0.25 in, 6 mm) to "golf ball" sized (1.75 in, 43 mm), to, in rare cases, "softball" sized or greater (­>4.25 in, 108 mm).

Hailstorm

A storm of hail. If the hail is sufficiently large, it can cause damage to cars or even people.

Artificial snow

Snow can be also manufactured using snow cannons, which actually create tiny granules more like soft hail (this is sometimes called "grits" by those in the southern U.S. for its likeness to the texture of the food). In recent years, snow cannons have been produced that create more natural looking snow, but these machines are prohibitively expensive.

Watermelon snow

A reddish/pink colored snow that smells like watermelons, and is caused by a red colored green alga called chlamydomonas nivalis

Penitentes

Tall blades of snow found at high altitudes

See also