Atmospheric River Brings Flood Risks, Avalanche Fears To Pacific Northwest

The Pacific Northwest is at risk of seeing some major flooding and even avalanches due to an "extreme" atmospheric river, according to CNN.

The National Weather Service in Portland tweeted that low pressure forming over the Pacific created this atmospheric river, "which is a narrow ribbon of enhanced moisture transport." This "river" is expected to trudge across the region with heavy rain. Residents will see the worst of it starting Monday morning (February 28) through Tuesday morning (March 1).

That also means potential "hazardous" weather events, including huge floods and avalanches in some areas. Avalanche warnings have been issued in the Cascades, and over five million people across Idaho, Oregon, and Washington are under flood watches, including Seattle, reporters say.

Weather experts say the warming temperatures, melting snowpack, and excessive rain will make the threat of avalanches "high."

"Avalanche warnings have been issued for almost all of our forecasting zones," according to the Northwest Avalanche Center. "Triggering a slide is likely and will be big enough to bury or kill you. Avoid travel in or below avalanche terrain."

The extra rain and snowmelt mean more runoff, increasing the risk of floods for several rives in Washington and Willamette Valley in Oregon, the Weather Prediction Center says.

Meteorologists say the atmospheric river will begin to weaken by Wednesday (March 2) with lighter rain and snow showers for the rest of the week.