Blizzard
A blizzard is a severe winter storm characterized by strong winds and blowing snow. The National Weather Service defines a blizzard as a large amount of falling or blowing snow with winds greater than 35 miles (56 kilometers) per hour and visibility reduced to 0.25 mile (0.4 kilometer) for at least three hours. A severeblizzard is defined as having wind speeds in excess of 45 miles (72 kilometers) per hour with temperatures of 10°F (−12°C) or lower.
Most blizzards are accompanied by heavy snowfalls and temperatures of 20°F (−6°C) or lower. The falling and blowing of fine, powdery snow during a blizzard sometimes reduces visibility to less than a few yards (meters).
Blizzards create conditions that are dangerous for motorists and pedestrians. Commerce and transportation systems typically grind to a halt and roofs may collapse under the weight of the snow. Many lives are lost in blizzards due to hypothermia, a drastic drop in body temperature; frostbite, a freezing of the skin; or overexertion while shoveling snow.
Blizzards occur mainly in Canada, the United States, Russia, and the former Soviet Republics, central and northern Europe, and central and northern Asia. The United States usually experiences one to seven blizzards per year, although some winters have recorded as many as thirty-five. Blizzards occur in the United States primarily during the months of December through March.
Blizzards and lake effect snows
A blizzard is a severe storm, potentially life threatening, caused by wind-driven snow. Although many blizzards involve heavy snow falls, smaller snow amounts may still be driven to blizzard conditions of low visibility and extreme wind chill.
The United States National Weather Service (NWS) takes a broader approach to the designation of ablizzard. NWS classifies a storm as a blizzard if it manifests large amounts of snowfall, has blowing snow in near gale force winds (generally about 35 mph, or 30 knots), or has a combination of wind and snow that reduces visibility for more than a few hours. Severe conditions that are not quite blizzard-like are classified as severe winter storms.
Many areas near the Great Lakes in the United States and Canada are subject to frequent and severe blizzards due to lake effect snow. This is a meteorological phenomena created by Arctic cold fronts--sweeping generally west to east through Canada and the northern portion of the United States--colliding with the relatively warmer air overlying the Great Lakes. Although lake effect snow can occur over any large body of water in the world, in North America lake effect snows are most frequently associated with the Great Lakes.
The combination of moist, unstable air and Arctic cold can produce locally heavy snows, especially on areas immediately east of the advancing cold front. Lake effect snowstorms are unique because they can manifest from otherwise dry cold fronts that produce clear cold weather in other parts of the country. Lake effect snow storms are not associated with advancing cells of low pressure, but rather dense, high-pressure, Arctic cold fronts.
Lake effect snow may contribute to more than half the annual snowfall for some areas on the east or southeast side of the Great Lakes. If winds are light enough to move the falling snow onshore (but not strong enough to blow the developing system over an area too quickly), snowfalls measuring 4-6 feet are possible.
Generally, the greater the temperature differential between the relatively warmer air over the lake and the advancing cold front, the more pronounced the lake effect snowfall. If the differential is great enough and the moisture of the rising unstable air high enough, thundersnow may develop (a thunderstorm with snow instead of rain).
A blizzard is a severe winter storm characterized by strong winds and blowing snow. The National Weather Service defines a blizzard as a large amount of falling or blowing snow with winds greater than 35 miles (56 kilometers) per hour and visibility reduced to 0.25 mile (0.4 kilometer) for at least three hours. A severeblizzard is defined as having wind speeds in excess of 45 miles (72 kilometers) per hour with temperatures of 10°F (−12°C) or lower.
Most blizzards are accompanied by heavy snowfalls and temperatures of 20°F (−6°C) or lower. The falling and blowing of fine, powdery snow during a blizzard sometimes reduces visibility to less than a few yards (meters).
Blizzards create conditions that are dangerous for motorists and pedestrians. Commerce and transportation systems typically grind to a halt and roofs may collapse under the weight of the snow. Many lives are lost in blizzards due to hypothermia, a drastic drop in body temperature; frostbite, a freezing of the skin; or overexertion while shoveling snow.
Blizzards occur mainly in Canada, the United States, Russia, and the former Soviet Republics, central and northern Europe, and central and northern Asia. The United States usually experiences one to seven blizzards per year, although some winters have recorded as many as thirty-five. Blizzards occur in the United States primarily during the months of December through March.
Blizzards and lake effect snows
A blizzard is a severe storm, potentially life threatening, caused by wind-driven snow. Although many blizzards involve heavy snow falls, smaller snow amounts may still be driven to blizzard conditions of low visibility and extreme wind chill.
The United States National Weather Service (NWS) takes a broader approach to the designation of ablizzard. NWS classifies a storm as a blizzard if it manifests large amounts of snowfall, has blowing snow in near gale force winds (generally about 35 mph, or 30 knots), or has a combination of wind and snow that reduces visibility for more than a few hours. Severe conditions that are not quite blizzard-like are classified as severe winter storms.
Many areas near the Great Lakes in the United States and Canada are subject to frequent and severe blizzards due to lake effect snow. This is a meteorological phenomena created by Arctic cold fronts--sweeping generally west to east through Canada and the northern portion of the United States--colliding with the relatively warmer air overlying the Great Lakes. Although lake effect snow can occur over any large body of water in the world, in North America lake effect snows are most frequently associated with the Great Lakes.
The combination of moist, unstable air and Arctic cold can produce locally heavy snows, especially on areas immediately east of the advancing cold front. Lake effect snowstorms are unique because they can manifest from otherwise dry cold fronts that produce clear cold weather in other parts of the country. Lake effect snow storms are not associated with advancing cells of low pressure, but rather dense, high-pressure, Arctic cold fronts.
Lake effect snow may contribute to more than half the annual snowfall for some areas on the east or southeast side of the Great Lakes. If winds are light enough to move the falling snow onshore (but not strong enough to blow the developing system over an area too quickly), snowfalls measuring 4-6 feet are possible.
Generally, the greater the temperature differential between the relatively warmer air over the lake and the advancing cold front, the more pronounced the lake effect snowfall. If the differential is great enough and the moisture of the rising unstable air high enough, thundersnow may develop (a thunderstorm with snow instead of rain).