The great rainstorm of 2010 in California has been impressive, with 15 feet of snow in the Sierra Nevadas, inches of rain on the coast, and so on. But it pales against the “Super Ark” storm of 1861-62, a 45-day beast that made unusable something like one-third of California’s taxable land, and created massive lakes in the Central Valley.
Beginning on Christmas Eve, 1861, and continuing into early 1862, an extreme series of storms lasting 45 days struck California. The storms caused severe flooding, turning the Sacramento Valley into an inland sea, forcing the State Capital to be moved from Sacramento to San Francisco for a time, and requiring Governor Leland Stanford to take a rowboat to his inauguration. William Brewer, author of “Up and down California,” wrote on January 19, 1862, “The great central valley of the state is under water—the Sacramento and San Joaquin valleys—a region 250 to 300 miles long and an average of at least twenty miles wide, or probably three to three and a half millions of acres!” In southern California lakes were formed in the Mojave Desert and the Los Angeles Basin. The Santa Ana River tripled its highest-ever estimated discharge, cutting arroyos into the southern California landscape and obliterating the ironically named Agua Mansa (Smooth Water), then the largest community between New Mexico and Los Angeles. The storms wiped out nearly a third of the taxable land in California, leaving the State bankrupt
It, in turn, however, doesn’t even show up in the 300-year cycle of mega-storms that have hit the state, the sort of cataclysmic winter rains that don’t just flood, but transform geography and settlement patterns.