According to the National Weather Service, blizzards are strong storm systems that occur most frequently in the Northern and Midwestern United States. Blizzards can create life-threatening conditions because of blowing snow and high winds. These strong storm systems can also create power outages, frozen pipelines and cut off regular fuel sources. It is often dangerous to travel in blizzard conditions, and people who are caught outside in these storm systems can become hypothermic because of low temperatures and high winds.
Blizzards commonly develop on the northwestern side of intense winter storm systems. The difference in low-pressure systems and high-pressure storm systems create a tight pressure gradient, which is the cause of strong winds, says weather.com. This occurs when the jet stream dips south while cooler air from the north clashes with warmer air from the south, the National Weather Service says.
Blizzards can occur during snowfall or after snowfall. High winds pick up falling snow or grounded snow and blow it around, causing low visibility, usually one-quarter mile or less, for three or more hours at a time, the National Weather Service says.
Blizzards commonly occur with temperatures around or below 20 degrees Fahrenheit, says weather.com. These low temperatures combined with strong winds create a low wind-chill factor, which is the amount of cooling someone feels from the combination of temperature and wind speed. Although blizzards can create very low wind-chill factors, heavy snowfall and severe cold are not required for blizzard conditions, according to the National Weather Service.