An arctic air blast is sweeping south from Canada, spreading into the northern United States. Meanwhile, residents of the Pacific Northwest are bracing for possible mudslides and levee failures as floodwaters slowly recede.

Heavy rain​ has triggered flooding, rescues and road closures in Washington state, with Gov. Bob Ferguson declaring a statewide emergency​.

The Pacific Northwest is expected to see up to seven inches of rain this week, as the eastern United States braces for arctic cold.

Officials say dangerous flooding could force 100,000 people to evacuate.