A storm that was pounding California's Sierra Nevada with snow Tuesday took aim at the Colorado Rockies and could roll east and slam the Appalachians on Thanksgiving Day, bringing unsettled travel weather to millions of Americans hitting the skies and roads for the holiday weekend.

A high-impact winter storm packing heavy snow and rain has moved into the Northeast, leading to last-minute travel troubles as millions of people across the U.S. gather with family and friends on Thanksgiving to celebrate the holiday.