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The Stages of a Blizzard

The National Weather Service Weather Forecast Office of Omaha, Nebraska, considers blizzards to be "the most dramatic and dangerous winter storm." These winter storms are more than just significant amounts of snowfall. The various stages of a blizzard are what make this storm as dangerous as it is. In fact, a massive blizzard in Chicago, Illinois, in February 2011 caused at least nine deaths.

  1. Decreasing Temperatures

    • Blizzards are characterized by low temperatures, a process that occurs in the early stage of the storm. According to The Weather Channel, average blizzards have temperatures of about 20-degrees Fahrenheit and below, and severe blizzards get down to 10 degrees F and below. When cold and warm air combines -- caused by a dip in the jet stream -- the blizzard storm forms to create cold atmospheric temperatures suitable for snow. A reduction in temperature can indicate that a blizzard is under way, as this drop prepares the atmosphere for severe snowfall.

    Increased Snowfall

    • Snowfall is an early stage of the blizzard. As the temperature drops, snow begins to fall more severely. It may start out slow at first, but the snowfall picks up until it becomes a continuous and consistent part of the storm. In the February 2011 blizzard in the Midwest, the heaviest part of the blizzard caused 2 to 3 inches of snow to fall per hour, according to The Weather Channel. The National Snow and Ice Data Center records that in December 1947, a New York blizzard caused 2 feet of snowfall in 24 hours.

    Strong Winds

    • Strong winds come next during the blizzard to accompany the snowfall. The winds pick up the powdery snow and toss it around violently, such that clouds of white fill the view outside. According to The Weather Channel, a blizzard is defined by having winds of 35 mph or more. When blizzards occur over water, large waves can form, crashing onto the shore and flood what's in its path.

    Reduced Visibility

    • As the wind blows and the snow falls, visibility problems form. Blizzards often reduce visibility to less than ¼ mile, according to The Weather Channel. In severe conditions, whiteouts can occur. Whiteouts are disorienting weather phenomenons caused by snowfall and low clouds that create a white shield with visibility down to a matter of feet.

    Timeframe

    • Blizzards are defined as lasting for three hours or longer, from the beginning stages to the end. The December 1947 blizzard in New York was a long-lasting blizzard that kept up for 24 hours, according to the National Snow and Ice Data Center. The Weather Channel reports that the February 2011 blizzard in the Midwest spanned two days.

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