A blizzard is a severe winter storm characterized by strong winds, cold temperatures, and snow. Unlike a regular snowstorm, a blizzard is defined by sustained strong winds and very low visibility, even if new snow is not falling. This combination makes blizzards particularly dangerous and challenging.
The Special Ingredients for a Blizzard
Three specific elements must come together to create a blizzard: extremely cold air, sufficient moisture, and powerful winds.
Very cold air is necessary for snow to form and remain frozen as it falls. Temperatures must be at or below freezing (0 degrees Celsius or 32 degrees Fahrenheit) from the clouds all the way to the ground. This cold air often originates from polar regions, bringing frigid conditions across large areas.
Moisture in the atmosphere is required to produce snow. This moisture typically comes from a warm, moist air mass that rises over a colder air mass, or it can be drawn from large bodies of water. As the moist air cools, water vapor turns into ice crystals, forming snow.
Strong winds are a defining feature of a blizzard. These winds are sustained at 56 kilometers per hour (35 miles per hour) or more, and they pick up and blow around any existing snow on the ground. This blowing snow significantly reduces visibility and is a key factor distinguishing a blizzard from other snow events.
Why Blizzards are Super Strong
The combination of intense cold, abundant snow, and powerful winds makes blizzards strong and dangerous. The strong winds transform a heavy snowfall into a severe event.
Powerful winds lift fallen snow from the ground, creating blowing snow. This dramatically reduces visibility, often to 0.4 kilometers (one-quarter mile) or less. It makes seeing extremely difficult. The combination of falling snow and blowing snow can lead to “whiteout” conditions, where the sky and ground blend into one indistinguishable white expanse.
Strong winds contribute to wind chill, making the air feel much colder than its actual temperature. Wind chill occurs because the wind removes body heat more quickly, making exposed skin feel significantly colder and increasing the risk of frostbite and hypothermia. The sustained wind, extreme cold, and poor visibility create a hazardous winter storm.