San Francisco — California's weather, like its social trends, moves eastward. The effect on the rest of the United States usually is not as direct as, say, the Hula-Hoop fad or college campus militancy. But though the waves that gouged this state's coast and the rain that induced landslides may not have reached Kansas City or Boston, the flooded lettuce, tomato, and other fields will soon mean higher food prices in those cities.
This ''wet season,'' with its seemingly endless series of storms, was much more severe in cumulative effect than the abnormally wet winter of 1981-82.
Figures on crop damage are still being collected, but the most recent statistics released by the California Department of Food and Agriculture showed that last week some 350,000 acres of farmland in the Sacramento and San Joaquin Valleys were flooded. Crops affected include artichokes, almonds, cauliflower, celery, cotton, garlic, lettuce, oats, onions, potatoes, rice, sorghum, strawberries, sugar beets, tomatoes, walnuts, and wheat.
Total damage in California from the winter storms is estimated at $524 million. That includes $158 million for more than 8,380 homes and 790 businesses and $121 million for public roads and other facilities. Thirty-two of the state's 58 counties have been declared eligible for federal and state disaster assistance, and eight more have applied.
Most agricultural producers don't want to discuss specific price effects, but supplies of many of those products will be short and prices could go up from 5 to 25 cents a pound, according to some sources.
Bob McGregor, chief statistician for the agriculture department, said rainfall has been up to 21/2 times ''normal'' in farming areas this winter. Planting of many crops has been delayed. Agricultural damage is at $300 million and climbing.
Looking at the damage done to agricultural, business, personal, and public property, some ask whether such losses were unavoidable. Yes and no, say experts studying the situation. Can they be avoided in future? Again, the answer is ambiguous.
Take, for example, the problems facing coastal communities, where homes and businesses have been battered by the recent storms. John Tinsley, a geologist with the United States Geological Survey (USGS) in Menlo Park, Calif., says the fact that coastal beaches have practically disappeared does not mean they won't reappear. It's a natural process, he says, that is ever recurring but has simply been more drastic this winter than for many years.
''If we have mild winters, the beaches will rebuild to some degree,'' Mr. Tinsley says. ''If we have entered a cycle of severe winters, as some believe, further erosion will occur.
''If you build a house or a restaurant on one of those beaches, you have to be prepared to take a loss,'' he adds. ''If you've got the sort of mind set that's amenable to that sort of thing, you're going to be comfortable living on the coast. If you want to spend enough, you can build something that will withstand almost anything - sort of like an offshore drilling rig.
''Geologically it's very clear what the process is. Sociologically, it's also unfortunately pretty clear what the process is. People do not investigate geologic hazards very thoroughly - or, they may be misled by the seller of a piece of property.
''Beaches are 'sand in transport.' They're not permanent features, and anyone who contends differently is guilty of misdirection.''
Tinsley says the same is true about cliffs: ''A sea cliff is an erosional feature. It's not going to stop eroding just because someone built on it.''
Californians can be heard saying, ''We're getting Oregon-Washington weather.'' It is true, says Tinsley, that such storms are more usual farther north. The impact on those states is different, he says, for several reasons. ''One is that it's cool there in summer and those states are generally devoid of the California beach culture; they're not motivated to build at the water's edge.''
Gerald Wieczorek, also a USGS geologist, has studied landslides in the San Francisco area these past two years.
''Last year,'' notes Dr. Wieczorek, ''there was just one dramatic storm. This year there has been a succession of less intensive ones, but the impact in northern California has been greater,'' partly because groundwater levels were high to start with this winter, and it took less to be soaked.
Proper study of building sites and planning of structures is the best answer, he says. Some local governments have tightened planning and zoning requirements, Wieczorek notes, with good results. San Mateo and Santa Clara Counties in the Bay Area and Los Angeles County have tight codes and county geologists to help enforce them.