7:37 pm - Friday August 22, 2014

Blizzards

blizzardA blizzard is a severe snowstorm characterized by strong winds. By definition, the difference between blizzard and a snowstorm is the strength of the wind. To be a blizzard, a snow storm must have sustained winds or frequent gusts that are greater than or equal to 56 km/h (35 mph) with blowing or drifting snow which reduces visibility to 400 meters or ¼ mile or less and must last for a prolonged period of time — typically three hours or more. Snowfall amounts do not have to be significant. Ground blizzards require high winds to stir up already fallen snow.

Causes of Blizzard

Blizzards are obviously related very closely to hurricanes, tornadoes, and weather fronts. For a blizzard to occur, there must be precise amounts of each of these things.

Snow storms can be caused by a warm front coliding with a cold front. This creates a low pressure zone. When clouds in the low pressure zone are filled with ice crystals, there are chances for a major blizzard. (Note: a warm front is basically a warm wind, and a cold front it a cold wind. When the two winds colide, they neutralize each other out in a way, and make a low pressure zone.)

Low pressure creates high powered winds, as the warmer air spirals into the low zone, and adds alot of movement. Therefore if a low pressure zone gets lower, the winds speed up.

For snow, there needs to be alot of moisture in the air. This can be gathered up if the low pressure zone goes over a large body of water, like an ocean or lake. This moisture will then cool off as it rises into the atmosphere.

Effects of Blizzard

It would depend where the blizzard hit. In a rural area, probably some animal and plant life loss, as well as snow pile ups. On a city, human life and material loss. The people that are lost often die from hypothermia or many other ailments as well as animals for many of the same reasons. Both of those depending on the intensity of the blizzard.

The primary dangers are from severely reduced to zero visibility due to blowing snow, a state called “whiteout”, accompanied by drifting. If one is caught out in a car in a blizzard, the hazards are grave. A second problem is that the high winds combined with cold temperatures result in dangerous wind-chill factors. For example, at an outside temperature of 0°F combined with a 40-MPH wind has the chilling effect of still air at -53°F. A third issue is that blizzards can damage power lines directly, or break tree limbs that fall on the lines. Loss of power in many homes during a blizzard can quickly reduce the inside temperature to dangerously low levels, freeze water pipes, etc. The weight of snow can cause roofs to collapse, too.

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