Washington state braces for dangerous flooding as thousands could face evacuation orders

Residents began packing up and fleeing rising rivers in western Washington state Wednesday as a new wave of heavy rain swept into a region still reeling from a storm that triggered rescues and road closures a day earlier.

In the Pacific Northwest, an atmospheric river was swelling rivers toward record levels, with major flooding expected in some areas including the Skagit River, a major agricultural valley north of Seattle. In the town of Mount Vernon, officials ordered residents within the river's floodplain to evacuate.

Earlier in the day, dozens of vehicles were backed up at a sandbag-filling station in the town as residents prepared for what Mayor Peter Donovan described as "what increasingly appears to be a worst-case scenario here."

The Skykomish River roars by a cabin on Dec. 10,