Snow alone does not make a blizzard. The official definition requires sustained winds of at least 35 miles per hour and visibility reduced to a quarter mile or less by falling or blowing snow, lasting three hours or more.

These conditions create whiteout situations where horizon and sky merge. Travel becomes dangerous or impossible. Drifting snow can bury roads and vehicles within hours. Temperatures are usually low, but the wind is the critical factor that turns a snowstorm into a blizzard.

The Great Plains and the northeastern United States see the most frequent events, often when strong low-pressure systems draw cold air southward. Warnings give residents time to stock supplies and avoid travel.

• Requires high winds and low visibility in snow
• Creates whiteout conditions
• Common on plains and coastal regions
• Demands early warnings and preparation