Weekly Weather Event -Week of Sept. 27September 27, 2019
The National Weather Service has issued a potentially historic early-season winter storm warning for large swaths of the Northern Rockies this weekend. Heavy snow is expected throughout northern Montana, bringing 15 to 36 inches of snow in the plains and higher accumulations expected in the mountains. Gusting winds could reach up to 40 miles per hour, resulting in windchill temperatures hovering between 0° and 10° F. Certain regions may see blizzard conditions throughout the weekend.
Blizzards are winter storms primarily characterized by reduced visibility, with blowing snow and high winds making it difficult to see. Officially, visibility must be reduced to ¼ of a mile and winds must be at last 35 mph for at least 3 hours for a storm to be classified as a blizzard. Blowing snow is usually result of snowfall being picked up by strong winds, winds can instead pick up snow that has already fallen on the ground, creating a ground blizzard. While many blizzards also bring heavy snow and extreme cold, these factors are not necessary to qualify a winter storm as a blizzard.
Because blizzards reduce visibility, travelling through whiteout conditions can be especially dangerous. Heavy snow can lead to downed powerlines and trees, whereas strong winds and cold temperatures can result in low windchill values, increasing the risk of hypothermia and frostbite. The National Weather Service recommends limiting time outside during blizzard conditions and covering exposed skin.