Atmospheric River Sparks Flooding Threat in Two States

The National Weather Service (NWS) said Friday that California and Oregon will see a "flooding threat" this weekend because of an atmospheric river hitting the region.

Why It Matters

The potential for flooding in both states could lead to saturated soils, high river levels and high rainfall totals up to 7 inches, the NWS Weather Prediction Center said in a post on X (formerly Twitter).

The West Coast has had harsh weather the past week amid widespread rain and rough seas. Currently, portions of Northern California and southern Oregon are under gale warnings, high surf warnings and hazardous seas warnings, the NWS said.

What To Know

An atmospheric river is a region, typically narrow, that carries the most moisture outside of the tropics, according to the National Oceanic and Atmospheric Administration.

NWS Weather Prediction Center meteorologist Rich Otto told Newsweek on Friday that this is the "season" for these atmospheric river events to occur. Otto said the event could start Friday evening but dip in intensity Saturday during the day, then pick back up that night.

People look at the collapsed pier at the Santa Cruz Wharf in Santa Cruz, California, on Monday. An atmospheric river is threatening to bring flooding in California and Oregon this weekend. Photo by DANIEL DREIFUSS/AFP via Getty Images

Otto also pointed to another area of concern, saying that if burn scar regions get a lot of rain the result could be a flash flood or debris flow.

Portions of Northern California are also under a flood watch this weekend, and the NWS said that "there will be an increased risk of rock and land slides along roadways" in the affected areas.

Earlier this week, a portion of the Santa Cruz pier collapsed amid a high surf warning. The NWS warned residents and beachgoers of 30- to 40-foot waves, and even ones up to 60 feet, "at favored spots."

What People Are Saying

Otto told Newsweek that even though this is a typical time for such atmospheric river events, it is a "little unusual for the frequency these events are occurring." He added that the region has had 5 to 10 inches of rain as a result of other atmospheric river events recently.

WeatherNation wrote on X on Thursday about California's recent weather, saying: "The West Coast isn't catching a break just yet. Around Fort Bragg, CA, massive waves persist off the coast, and the moisture from the Atmospheric River will persist in bringing valley rainfall and mountain snowfall inland."

What Happens Next

After the rain picks back up on Saturday night, the atmospheric river event will come to an end on Sunday night, but only temporarily.