Severe weather is dangerous weather that can cause problems and death. It includes blizzards, droughts, hurricanes, tornadoes, and thunderstorms. Blizzards have blowing snow and reduced visibility lasting over 3 hours. Droughts are a lack of precipitation that can last for months or years. Hurricanes gain power over warm ocean waters with winds between 75-200 mph usually lasting over a week. Tornadoes are rotating columns of wind that cause great destruction. Thunderstorms involve lightning, thunder, gusty winds and heavy rain.