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"Snowstorm" redirects here. For other uses, see Snowstorm (disambiguation). A winter storm is an event in which the dominant varieties of precipitation are forms that only occur at cold temperatures, such as snow or sleet, or a rainstorm where ground temperatures are cold enough to allow ice to form (i.e. freezing rain). In temperate continental climates, these storms are not necessarily restricted to the winter season, but may occur in the late autumn and early spring as well. Very rarely, they may form in summer, though it would have to be an abnormally cold summer, such as the summer of 1816 in the Northeast United States of America. In many locations in the Northern Hemisphere, the most powerful winter storms usually occur in March (such as the 1993 Superstorm) and, in regions where temperatures are cold enough, April. Approaching winter storm in Salt Lake City.
Snowstorms are storms where large amounts of snow fall. Snow is less dense than liquid water, by a factor of approximately 10 at temperatures slightly below freezing, and even more at much colder temperatures. Therefore, an amount of water that would produce 0.8 in. (2 cm.) of rain could produce at least 8 in (20 cm) of snow. Two inches of snow (5 cm.) is enough to create serious disruptions to traffic and school transport (because of the difficulty to drive and maneuver the school buses on slick roads). This is particularly true in places where snowfall is uncommon but heavy accumulating snowfalls can happen (e.g., Atlanta, Seattle, London, Dublin, Canberra, Vancouver and Las Vegas). In places where snowfall is common, such as Utica, Detroit, Denver, Ottawa, Montreal, Quebec City, Chicago, Pittsburgh, Buffalo, NY, Toronto and Minneapolis, such small snowfalls are rarely disruptive, because winter tires are used, though snowfalls in excess of 6 in (15 cm) usually are. A massive snowstorm with strong winds and other conditions meeting certain criteria is known as a blizzard. A large number of heavy snowstorms, some of which were blizzards, occurred in the United States during 1888 and 1947 as well as the early and mid-1990s. The snowfall of 1947 exceeded two feet with drifts and snow piles from plowing that reached twelve feet and for months, temperatures did not rise high enough to melt the snow. The 1993 "Superstorm" was manifest as a blizzard in most of the affected area. Large snowstorms could be quite dangerous: a 6 in. (15 cm.) snowstorm will make some unplowed roads impassible, and it is possible for automobiles to get stuck in the snow. Snowstorms exceeding 12 in (30 cm) especially in southern or generally warm climates will cave the roofs of some homes and cause the loss of power. Standing dead trees can also be brought down by the weight of the snow, especially if it is wet or very dense. Even a few inches of dry snow can form drifts many feet high under windy conditions.
Dangers of Snow
Snowstorms are usually considered less dangerous than ice storms. However, the snow brings secondary dangers that can affect us thoroughly if we are near the place. Mountain snowstorms can produce cornices and avalanches. An additional danger, following a snowy winter, is spring flooding if the snow melts suddenly due to a dramatic rise in air temperature. Deaths can occur from hypothermia, infections brought on by frostbite or car accidents due to slippery roads. Fires and carbon monoxide poisoning can occur after a storm causes a power outage. There are also several cases of heart attacks caused by overexertion while shovelling heavy wet snow.
Wintry showers or wintry mixes
Many factors influence the form precipitation will take, and atmospheric temperatures are influential as well as ground conditions. Sometimes, near the rain/snow interface a region of sleet or freezing rain will occur. It is difficult to predict what form this precipitation will take, and...