The National Weather Service said the fog could lead to black ice and limited visibility, and urged drivers to exercise caution.

More than 18 million people are under winter weather alerts across the West and Midwest as storms are forecast to bring heavy snows and bitter winds.

Around 20 million people across the West and Midwest are under winter alerts Saturday as a fast-moving storm delivers heavy snow, strong winds and blasts of cold that is blanketing cities like Chicago.

Winter storm warnings have been issued for several US states across the West and Northwest amid heavy snowfall and dangerous travel conditions in various areas.

With snow falling, the National Weather Service expanded a winter storm warning to include Ames and surrounding Boone, Story and Marshall counties.

With recent snow events, and the approaching Winter Solstice, you may notice Winter Weather Advisories, Winter Storm Watches, and Winter Storm Warnings being reported, as issued by the National Weather Service.

Understanding the Watch, Warning, and Advisory Hierarchy Let's be real, the National Weather Service throws around terms like watch, warning, and advisory, and most people just know something bad is coming.

The next plume of moisture is moving through western Montana this evening. The atmosphere has become unstable, and a few heavier bands of snow showers are devel