That's because of "another atmospheric river event" that will bring copious rainfall to coastal and valley locations and 3 to 4 feet of snow to the Sierra, forecasters said. The storm will move into the Rockies by midweek: "One tricky travel area will be in and around the Denver area as snow spreads across the area on Wednesday,

Millions of Americans across the U.S. have started to pack the roads and airports ahead of Thanksgiving, but a powerful storm moving from coast to coast could snarl travel before the holiday and as people begin their journeys home after celebrating with family and friends.