Blizzard
From Wikipedia, the free encyclopedia
- This article is about winter storm condition. For other uses, see Blizzard (disambiguation).
A blizzard is a severe winter storm condition characterized by low temperatures, strong winds, and heavy blowing snow. They are formed when a high pressure system, also known as a ridge interacts with a low pressure system, this results in the advection of air from the high pressure zone into the low pressure area. The strength of the high and depth of the low will determine indirectly how strong winds between the systems will be based upon the pressure gradient between. The term blizzard is often misused by the media to describe a large winter storm which may or may not contain strong winds and often will not meet official blizzard criteria as defined by the local weather agency or governing body.
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[edit] Definition
Blizzards occur throughout the world and in North America are particularly common to the North-eastern U.S and Maritime Canada. Because the factors involved with the classification of winter storms are complex, there are many different definitions of the word blizzard. A major consensus is that in order to be classified as a blizzard, as opposed to merely a winter storm, the weather must meet several conditions: the storm must decrease visibility to a quarter of a mile or 400 meters, include snow or ice as precipitation, and have wind speeds of at least 35 miles per hour or 56 kilometres per hour (which would be seven or more on the Beaufort Wind Scale) for at least three consecutive hours.
Another standard, according to Environment Canada, is that the winter storm must have winds of 40 km/h (25 mph) or more, have snow or blowing snow, visibility less than 1 km (about 5⁄8 mile), a wind chill of less than −25 °C (−13 °F), and that all of these conditions must last for 3 hours or more before the storm can be properly called a blizzard.
When all of these conditions persist after snow has stopped falling, meteorologists refer to the storm as a Ground blizzard.
An extreme form of blizzard is a whiteout, when downdrafts coupled with snowfall become so severe that it is impossible to distinguish the ground from the air. People caught in a whiteout can quickly become disoriented, losing their sense of direction. This poses an extreme risk to the aviation community when flying at the altitude of the storm or navigating an airport, severe ice accretion on the wings may also result.
[edit] Etymology
The word blizzard is of unknown origin, but may originate from the surname Blizzard. It was first widely used after the great United States winter storm, now known as the "Blizzard of 1880."
[edit] Climatology
Severe blizzards can occur in conjunction with polar cyclones.
Most blizards that cause much damage happen in the colder enviroments including the north of the US and much of Canada.
Certain types of blizzards in the northeastern United States are colloquially known as Nor'easters. In the Upper Midwest, a northerly weather pattern deemed likely to produce blizzards is called an Alberta clipper.
[edit] Famous U.S. Blizzards
There have been many devastating blizzards throughout U.S. History.
It is not uncommon for a region of the United States or North America to be struck by two devastating winter storms in one season. The Great Blizzard of 1888 paralyzed the Northeastern United States. In that blizzard, 400 people were killed, 200 ships were sunk, and snowdrifts towered 15 to 50 feet high. Earlier that year, the Great Plains states were struck by the Schoolhouse Blizzard that left children trapped in schoolhouses and killed 235 people.
These unpredictable storms can come without much warning, causing damage and destruction to humans and infrastructure. The Armistice Day Blizzard in 1940 caught many people off guard with its rapid and extreme temperature change. It was 60 degrees Fahrenheit in the morning, but by noon, it was snowing heavily. Some of those caught unprepared died by freezing to death in the snow and some while trapped in their cars. Altogether, 154 people died in the Armistice Day Blizzard.
One-hundred five years to the day (March 12) after the blizzard of 1888, a massive blizzard, nicknamed the Storm of the Century, hit the U.S in 1993. It dropped snow over 26 states and reached as far north as Canada and as far south as Mexico. In many southern U.S. areas, such as parts of Alabama, more snow fell in this storm than ever fell in an entire winter. Highways and airports were closed across the U.S. As a wider effect, the storm spawned 15 tornadoes in Florida. When the Storm of the Century was over, it affected at least half the of U.S. population; 270 people died and 48 were reported missing at sea. ʕʕ ǍĹĹǒṜǎ ʢʢ
[edit] List of Famous Blizzards
- The Schoolchildren's Blizzard
- The Blizzard of 1888
- The Blizzard of '77
- The Blizzard of 1978
- The 1993 North American Storm Complex
- The 1996 Blizzard
- The Blizzard of 2005
- Category:Blizzards
[edit] See also
[edit] External links
- Natural Disasters – Blizzards Great research site for kids.
- Digital Snow Museum Photos of historic blizzards and snowstorms.
- Blizzards Photo Gallery Photos of huge U.S. snowstorms, plus blizzard survival info — all from AOL Research & Learn
