A huge Pacific storm that spread from one end of the state to the other dropped up to an inch of rain across San Diego and Riverside counties Monday.

As the storm breaks up, it is expected to leave behind huge swells for surfers and more than a foot of fresh powder in the Southern California mountains. But the U.S. Coast Guard warned mariners to take precautions as powerful waves are forecast to linger for several days.

"It covers the entire state," Stan Wasowski, a forecaster for the National Weather Service in Rancho Bernardo, said of the storm. "This time everybody got it, everywhere from the Oregon border down to the Mexican border."

The storm also was good news for Southern California's water supply, as it dumped several feet of snow on the Sierra Nevada, according to The Associated Press.

"They're getting hit really hard," Wasowski said. "They're measuring snow in feet. We're getting a lot of snowpack to build up that water supply."

But the moisture doesn't end the threat of rationing this summer.

"Obviously, we're hopeful," said San Diego County Water Authority spokesman John Liarakos. "But it's going to take a whole lot more snow falling up there to get it back even to an average year."

When the California Department of Water Resources measured the snow depth in the Sierra Nevada on Feb. 1, it was 40 percent below average. It will measure again next month.

Liarakos said that three-quarters of the region's water comes from mountain snowpack.

"We still feel that mandatory restrictions are in the offing for July of this year," he said.

Driven by winds of up to 30 mph, rain fell hard on most areas Monday morning, then eased in the afternoon.

Rainfall totals ranged from 1.68 inches at Julian to a fifth of an inch at Oceanside, according to the National Weather Service in Rancho Bernardo.

Other totals included: Palomar Mountain, 1.64 inches; Murrieta, 1.21 inches; Ramona, 0.94 inch; Rancho Bernardo, 0.84 inch; Valley Center, 0.78 inch; Encinitas, 0.75 inch; Poway, 0.75 inch; Temecula, 0.75 inch; Lake Elsinore, 0.69 inch; San Marcos, 0.55 inch; Escondido, 0.54 inch; Solana Beach, 0.53 inch; Fallbrook, 0.49 inch; Vista, 0.48 inch; Carlsbad, 0.36 inch; and Menifee, 0.30 inch.

Carole Bell, manager of the Santa Rosa Plateau Ecological Reserve, said the oak-forested park near Murrieta received a little more than an inch.

"The rains are welcome, as they will keep our vernal pools full," Bell wrote in an e-mail. "These rains should encourage a beautiful wildflower display in April."

Monday was not the biggest rainfall day of the season, Wasowski said.

The season's largest one-day total was 1.88 inches on Dec. 17 and 1.51 inches on Feb. 7.

Above 4,500 feet, snow fell.

Wasowski said 5 to 8 inches was expected in San Diego County's mountains and 12 to 18 inches in the Riverside County mountains through Tuesday.

And mountain resorts were getting dumped on.

"We've got 7 to 10 inches of nice, fluffy power and it's still snowing," said Mindy Clark, marketing coordinator for Big Bear Mountain Resorts, which operates the Snow Summit and Bear Mountain ski areas.

Clark said she expects droves of skiers and snowboarders to head up today to take advantage of a relatively rare opportunity.

"The powder hounds, as we call them, will be up here," she said.

Oceanside lifeguard Capt. Bill Curtis said surfers are expected to be out in force to challenge strong storm waves, after ferocious winds kept surfers to a minimum.

"The wind's been blowing so hard that there hasn't been hardly anybody out here at all," Curtis said.

Farther south, San Diego lifeguards rescued a Chula Vista man and his son who went out in kayaks early Monday off La Jolla.

The fierce winds pushed them more than two miles offshore and knocked one of the kayaks over.

Lt. Andy Lerum said they managed to call for help on a cell phone.

The Coast Guard in San Diego warned that winds gusting to 45 mph and waves cresting at 10 feet or higher were a recipe for disaster, and the agency asked mariners to refrain from heading out for the next few days unless they are properly equipped.

National Weather Service forecaster Noel Isla said there is a slight chance of a little more rain Tuesday morning, but it should taper off by afternoon.

For the rest of the week, sunny skies and temperatures warming into the 70s are in the forecast, he said.

As expected, periods of heavy rainfall midday led to a spike in crashes around the county, according to the California Highway Patrol's Web site.

But authorities reported no serious-injury crashes in North County.

Contact staff writer Dave Downey at (760) 745-6611, ext. 2623, or ddowney@nctimes.com.