Full List of Weather Warnings as ‘Strong’ Atmospheric River Hits

The National Weather Service (NWS) has a slew of weather alerts and warnings in place across the Pacific Northwest amid a prolonged “strong” atmospheric river that hit the region on Monday.

Why It Matters

After a series of back-to-back atmospheric rivers in December, California hasn’t seen many atmospheric rivers, which typically plague the state during the winter months.

One such storm arrived in the Pacific Northwest over the weekend. The NWS office in Sacramento said its impacts will continue over the next couple days, according to one of its forecasts. People in the impacted areas can expect heavy rain, snow and the threat of floods.

What To Know

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 the National Oceanic and Atmospheric Administration (NOAA).

As of Monday morning, the weather alerts in place across the Pacific Northwest include:

• winter storm warning
• winter weather advisory
• high wind warning
• flood warning
• gale warning
• flood advisory
• small craft advisory
• lake wind advisory
• wind advisory
• flood watch

Most warnings were in place across northern California in the Sacramento forecast region.

According to a storm timeline shared by the NWS Sacramento office, storm impacts could persist across Northern California through Friday. The region is expecting scattered showers on Monday, with snow levels dropping to 6,000 feet, as well as some gusty winds. Heavy rain and snow will persist from Tuesday through Thursday, and snow levels will drop to 3,000 feet by Wednesday, or 1,500 feet for Shasta County.

Light showers will continue on Friday, as well as continued snowfall. Dry, breezy weather will return over the weekend.

In a post on X, formerly Twitter, NWS Sacramento warned of widespread rainfall amounts of 2 to 3 inches, with some areas seeing as high as 6 to 8 inches. The office advised people to avoid mountain travel until the storm had passed.

Meanwhile, weather alerts are also in place across Oregon and Washington, mostly winter storm-related warnings.

What People Are Saying

NWS meteorologist Sara Purdue told Newsweek: “Any of [the alerts] have the potential to be dangerous. The most concerning areas are where we have our winter storm warning out, because we are expecting near whiteout conditions, major travel delays, road closures and chain controls.”

A flood watch from NWS Sacramento said: “Periods of moderate to heavy rainfall are expected over the next 36 hours with totals 2 to 4 inches in the Valley, 3 to 8 inches in the foothills, and 5 to 10 inches in the mountains below 5500 feet. Heaviest period of rain will be this evening into Tuesday night.”

An NWS forecast said: “The strong atmospheric river bringing the heavy flooding rain concerns over northern California should persist through the first part of the week as a stationary front remains anchored in place. Multiple waves of low pressure will traverse this boundary, and this coupled with the Pacific moisture transport and upslope flow/forcing over the higher terrain of the coastal ranges and northern Sierra Nevada foothills should yield as much as an additional 5 to 10 inches of rain.”

What Happens Next

According to the NWS Climate Prediction Center, all of California is expected to experience near-normal precipitation for the next eight to 14 days. Temperatures look like they will be below normal for the entire state during the same time period, according to the center’s outlooks.