Map shows evacuations possible as one state gets more than a foot of rain

A map from the National Oceanic and Atmospheric Administration’s (NOAA) National Water Center revealed that several rivers in Washington state are expected to hit major flood levels this week as an atmospheric river inundates the region with significant rainfall exceeding a foot in some areas.

On the Water Center’s website, the “major flood” category warns that “extensive inundation of structures and roads, significant evacuations of people and/or transfer of property to higher elevations” is possible.

Newsweek reached out to NOAA by email for comment on Monday.

The flood forecasts come as a strong atmospheric river pummels the Pacific Northwest. The storm follows a weaker system that inundated the area over the weekend. Atmospheric rivers are a “long, narrow region in the atmosphere—like rivers in the sky—that transport most of the water vapor outside of the tropics,” according to NOAA.

The storms brought by atmospheric rivers are known for their heavy snow, heavy rain and strong winds. They more commonly affect the West Coast, particularly during the winter months. Although the storms can bring beneficial snow that helps supplement reservoirs throughout the summer dry season, they can also trigger deadly flooding, mudslides and widespread power outages.

On Monday, the current storm had prompted multiple NWS offices to issue numerous weather warnings across Washington and Oregon. The worst threats came from flooding and strong winds.

Eleven rivers are forecasted to reach major flood levels, according to the National Water Center. They are the Grays River at Covered Bridge near Rosburg, the Cowlitz River at Randle, the Cowlitz River at Packwood, the Nisqually River near National, the Puyallup River near Orting, the White River near Auburn, the Snoqualmie River at Snoqualmie Falls, the Snoqualmie River near Carnation, and the Skykomish River near Gold Bar.

In addition to the rivers forecast to hit major flood levels, numerous rivers throughout the state also are expected to hit the moderate flood category.

NWS offices in Seattle and Portland, Oregon, warned of significant and dangerous rainfall amounts over the next few days. Widespread amounts of 5 or more inches of rain are expected within the Portland forecast region, with some areas seeing more than 8 inches. Rain will be even worse in Washington, with the NWS Seattle office warning that widespread rainfall of 6 inches was expected, with some areas like Snoqualmie Pass expecting 15 inches.

The rain will fall over a period of 72 hours.

“Periods of heavy rain today through Wednesday will lead to concerns of river flooding, small stream flooding, urban flooding, and landslides beginning this afternoon,” NWS Portland posted on X.