Blizzards are severe storms which are marked by extremely low temperatures, high-speed winds and substantial snowfall. They are formed when a region of high atmospheric pressure, termed as a ridge, interacts with a region of low atmospheric pressure.
As a result of this, a phenomenon known as advection takes place, in which there is a rush of air from the high pressure region to the low pressure region. The visibility is reduced to less than a quarter of a mile.
Three factors necessary for blizzards to form
- Air below freezing point (typically 20 degrees F and below) that can cause snow, should be present both at the heights of the clouds and near the ground. As a result, snow is formed at the clouds, and near the ground, the snow is prevented from melting.
- There should be adequate moisture to help clouds develop, and result in precipitation. Wind blowing over a lake is a sure source of moisture.
- Warm air that rises over cold air should be present for the blizzard to develop, resulting in strong winds at more 35 miles per hour.