California officials today predicted sharp increases in the price of many vegetables and fruits in East Coast supermarkets as a result of the devastating storms that have damaged or delayed the harvest of millions of dollars of West Coast crops.

The rain abated today, after high waves, winds and floods had taken at least 19 lives, caused more than $160 million in damage and forced nearly 10,000 people from their homes.

But more rain was predicted for the weekend, and President Reagan promised California Gov. George Deukmejian more disaster aid after the president viewed some of the devastation from his helicopter as he flew from Santa Barbara to Los Angeles.

His route took him over Ventura County, a leading producer of lettuce, celery, broccoli and strawberries at this time of year but now awash from the week's deluge.

County Agriculture Commissioner W. Earl McPhail estimated that $9 million worth of crops already had been ruined.

Delays in harvesting crops in Ventura and other parts of the state are expected to have an even more serious effect on East Coast prices, expected to go up as supplies from the nation's largest vegetable-producing state take a sharp, if temporary, drop.

Gordon Heltzel, a program supervisor with the Federal State Market News Service, said wholesale prices for lettuce in San Francisco already had climbed 40 percent.

Damage to perishable crops because of rain-delayed transportation to the East Coast will affect prices, Heltzel said.

County officials estimated price increases of 5 cents to 25 cents per pound, depending on the commodity. Experience with previous California storms also indicates that disruption in planting schedules and fruit flower fertilization by bees now may affect supplies and prices in months to come.

But after the upcoming temporary price rise, Heltzel added, prices may plummet to unusually low levels as the delayed-harvest crops hit the market at the same time as regularly scheduled crops.

Anita Garcia of the California Office of Emergency Services said the state is seeking federal assistance for 32 counties affected by the most recent storm and a deluge that hit the state in January.

At least 1,600 homes were damaged or destroyed along the California coast, including dozens in the high-priced enclaves of Malibu, Santa Barbara and Stinson Beach.

The latest casualties included a 3-year-old boy suffocated in his bedroom Wednesday by a mud slide at Clear Lake in northern California.

Although among the most serious storms here in years, the current deluge has not yet reached the toll of death and destruction caused by storms in early 1980 and early 1982. The 1980 storm took 36 lives and did $320 million in damage, and last year's storm, centered in northern California, led to at least 31 deaths and damaged or destroyed about 6,500 homes. This year's storm had an unusual twist, a freak tornado that caused $15 million in damage and led to the death of one policeman in south-central Los Angeles when the helicopter in which he was riding crashed, but the annual rains continue to be an expected annoyance Californians choose to endure. "Everyone wants to live in a beautiful house overlooking the sea," Garcia said. So construction on steep hillsides, and annual grass and forest fires, lead to mud slides that do most of the damage.