Blizzards
are giant snow storms that disrupt peoples lives and cause
a lot of damage. Because of the wind that often accompanies
snow storms, it is often difficult to measure winter storms.
In basic terms, a blizzard is defined as a snow storm
that has winds blowing over 35 miles per hour, and visibility
(or the distance you can see) of less than 1/4 mile (400
meters). If these conditions last for three hours or more
the storm is called a blizzard. Information on measuring
different weather phenomenon can be found here.
Meteorologists measure
wind speed with an anemometer. You can make your own anemometer.
Snowfall is usually measured with a simple ruler but it
can be difficult to get an accurate measurement as snow
sometimes melts as it falls and can be blown around. Another
way to measure snowfall is to measure the amount of water
contained in the snow. Satellite images like the one above
are used to help meteorologists track and study storms.
They can also get information on size and strength of
storms. Here is a short MPEG2 motion satellite
image (you will need a media player to view it).
