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

Is it snowing in Buffalo? The calendar has turned to December, which means Mother Nature is off the inactive list.

Snow, high winds and below-average temperatures are sweeping from the Rockies to the Midwest, while an atmospheric river threatens flooding in the Pacific Northwest.

Such events distort the polar vortex, which causes Arctic air to descend into the U.S. and causes temperatures to plummet.

Chicago-area drivers could encounter slick conditions beginning late Saturday, as the first of multiple clipper systems ...