SAN FRANCISCO — IN recent years the Golden State of California has been battered by earthquakes, fires, and floods of seemingly Biblical proportions. As record-breaking rainfall and high winds continue to spread widespread destruction, residents are increasingly asking a difficult question: Is it just their imaginations, or is California more prone to natural calamity than other US states?
Perhaps so. California is indeed more vulnerable to natural disasters, says Ray Wilson, a geologist with the US Geological Survey, who heads the landslide-warning system in cooperation with the National Weather Service. The problem, he says, is essentially twofold: extreme weather changes and geological instability.
''Two separate climates are laid down on top of each other in California; we're climatically schizophrenic,'' says Wilson. Unlike the East Coast, where rainfall is scattered more evenly throughout the year, California's rainy season stretches from November to March, halving the year into very wet and very dry months. The rainfall from year to year fluctuates too: ''There's no such thing as an average year in California in terms of rain,'' he says. Droughts and fires are also the byproduct of such erratic weather patterns.
Another major threat comes from California's geology, especially in the coast ranges. Where New England's hills are made of hard rock such as granite, marble, and quartzite, California's rocks are relatively young and weak, and still very tectonically active. Add long dry spells and then concentrated rainfall to high hills, steep slopes, and soft rock, and it's a recipe for landslide disaster.
Still, the current round of rain and floods is unquestionably an historic tragedy. As of March 12, the storm's cost to California is estimated to exceed $2 billion, and may be the most expensive in state history, according to James Bailey of the Flood Operation Center in Sacramento. President Clinton declared much of California a major disaster area, authorizing emergency federal aid to individuals and local governments in 39 counties, including Marin, Mendocino, Monterey, Napa, Santa Cruz, and Sonoma.
At least six large rivers have overflowed, submerging entire towns. Fourteen people have died. Mudslides, falling rocks, and flooding have shut down countless bridges, roads, and highways throughout the state. Nearly 50,000 acres of prized agricultural farmland in the Central Valley and elsewhere are now underwater; the loss to crops is currently uncalculable.
From farmworkers in Pajaro to affluent winemakers in Napa Valley, more than 10,000 people have been forced to flee their homes, and 1,500 people are still packed into makeshift emergency shelters set up by the American Red Cross. In stricken Monterey County, residents have been rushed to safety by fire trucks, helicopters, and army vehicles, says Joseph Hertlein of the Monterey County Office of Emergency Services.
All 5,000 residents of Central Valley's Castroville, the artichoke capital of the world, were evacuated after torrential rain caused the sewage system to overflow, contaminating the water supply.
One reason the floods and mudsliding have been so bad is the condition of California's rivers. Due to the state's geological activity, river systems here are immature and underdeveloped. Flooded with water, dry stream beds of eroding rock turn to mud and overflow with dead trees and other debris, causing the flash floods that swallowed up much of California this past week.
Scientists agree that coming out of a prolonged drought, California officials might have predicted devastating floods. But, ''it's business as usual,'' says Walter Swain, a hydrologist with the US Geological Survey's water resources division. ''We should be anticipating such flooding. And with the land-use patterns that we have, it's inevitable that people will get flooded out.''