LOS ANGELES — California Gov. Jerry Brown asked President Trump on Friday to declare a major disaster in the state because of damage from a month of storms as more rain hit the south.

Brown’s letter said a powerful series of January storms brought “relentless” rain and high winds that caused flooding, mudslides, evacuations, erosion, power outages and at least eight deaths. Northern California was hardest hit.

Brown said the storm system was so severe and widespread that state and local governments need federal assistance to continue dealing with the problems it created.

In a separate action, the governor added Amador, Mono and Riverside to the 49 counties included in an emergency proclamation Brown issued last month.

A so-called atmospheric river weather system continued to pummel the upper two-thirds of the state this week but it weakened as if moved south down the coast on Friday.

The region from Ventura County to the Mexican border generally saw less than a half-inch of rain, although the National Weather Service said rain could continue to fall into Saturday, particularly in the mountains.

Thanks to a wet winter, downtown Los Angeles already has recorded 15.7 inches of rain since the Oct. 1 start of the water year, exceeding its annual rainfall total with the season far from over.

In the north, which reeled this week from fierce downpours, rising water and damaging mudslides, the rain tapered off. But problems persisted.

In Butte County, workers scrambled to rescue millions of baby salmon from a hatchery being buried in mud from the crumbling spillway of the Lake Oroville Dam. The fish were evacuated by tanker trucks.

Damage to the spillway could approach $100 million, officials said.

On Friday, state officials said they may be able to avoid emergency releases from the rain-choked reservoir by further sacrificing the concrete spillway.

“Basically it’s going to be a triage situation. We know we’re going to have erosion going on but it’s in the best interest of the lake right now to be able to keep using the spillway to evacuate water,” California Department of Water Resources spokesman Eric See.

A vast swatch of California’s northern interior and areas of the Central Valley remained under flood advisories or warnings into Saturday.

In the Sierra Nevada, winter storm warnings were to remain in effect until early Saturday in the greater Lake Tahoe area and Mono County.