- published: 17 Mar 2011
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A winter storm is an event in which the dominant varieties of precipitation are formed that only occur at low temperatures, such as snow or sleet, or a rainstorm where ground temperatures are low 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.
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.[citation needed] Therefore, an amount of water that would produce 0.8 in (20 mm) of rain could produce at least 8 in (20 cm) of snow. Two inches (5 cm) of snow 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 atypical but heavy accumulating snowfalls can occur (e.g., Dallas, Atlanta, Seattle, London, Dublin, Canberra, Vancouver and Las Vegas). In places where snowfall is typical, such as Utica, Kenosha, Milwaukee, Minneapolis, Detroit, Bismarck, Fargo, Rapid City, Sioux Falls, Omaha, St. Louis, Des Moines, Wichita, Denver, Albuquerque, Flagstaff, Ottawa, Montreal, Quebec City, Portland, Chicago, Syracuse, Buffalo, Cincinnati, Cleveland, Columbus, Philadelphia, Pittsburgh, and Toronto, such small snowfalls are rarely disruptive, because of effective snow and ice removal by municipalities, increased use of four-wheel drive and snow tires, and drivers being more used to winter conditions. Snowfalls in excess of 6 inches (15 cm) are usually universally disruptive.
In physics, energy (Greek: ἐνέργεια energeia "activity, operation") is an indirectly observed quantity. It is often understood as the ability a physical system has to do work on other physical systems. Since work is defined as a force acting through a distance (a length of space), energy is always equivalent to the ability to exert pulls or pushes against the basic forces of nature, along a path of a certain length.
The total energy contained in an object is identified with its mass, and energy (like mass), cannot be created or destroyed. When matter (ordinary material particles) is changed into energy (such as energy of motion, or into radiation), the mass of the system does not change through the transformation process. However, there may be mechanistic limits as to how much of the matter in an object may be changed into other types of energy and thus into work, on other systems. Energy, like mass, is a scalar physical quantity. In the International System of Units (SI), energy is measured in joules, but in many fields other units, such as kilowatt-hours and kilocalories, are customary. All of these units translate to units of work, which is always defined in terms of forces and the distances that the forces act through.