Why so many people were caught off-guard by these floods remains a mystery, but clearly these immigrants did not recognize the climatic warning signs. They had never experienced such extreme flooding in the 12 years since the Gold Rush began, although lesser floods were not uncommon. It appears that the Native American populations, who had lived in the region for thousands of years, had deeper insights to the weather and hydrology, and recognized the patterns that result in devastating floods. A piece in the Nevada City Democrat described the Native American response on January 11, 1862:
We are informed that the Indians living in the vicinity of Marysville left their abodes a week or more ago for the foothills predicting an unprecedented overflow. They told the whites that the water would be higher than it has been for thirty years, and pointed high up on the trees and houses where it would come. The valley Indians have traditions that the water occasionally rises 15 or 20 feet higher than it has been at any time since the country was settled by whites, and as they live in the open air and watch closely all the weather indications, it is not improbable that they may have better means than the whites of anticipating a great storm.
The specific weather pattern that the Native Americans of the West recognized and knew would bring particularly severe flooding is once again understood today. The powerful storms originate in the warm and moist tropical Pacific Ocean. Recent research describes these storms more broadly as “atmospheric rivers,” and they often result in the worst floods in not only the American West, but across the globe.
The tragic 1861-62 floods may have temporarily served to wake-up the residents of California and the West to the possible perils of their region’s weather They saw nature at its most unpredictable and terrifying, turning in a day or an hour from benign to utterly destructive. But the costs to the state went beyond the loss of life, property and resources: California’s spirit and confidence was badly shaken.
The lessons of the 1861-62 floods should provide the impetus for flood disaster planning efforts in a region where housing developments and cities are spreading across many floodplains. A critical element of living in a place like California is an awareness of these natural disasters, which requires a deep understanding of the natural patterns and frequencies of these events. Today we have building codes for earthquake safety, but millions of new westerners are not aware of the region’s calamitous climate history. Most have never even heard of the 1861–62 floods, and those may not have been the worst that nature can regularly dish out to the region. In a forthcoming book I co-wrote with Frances Malamud-Roam, THE WEST WITHOUT WATER: What Past Floods, Droughts, and Other Climatic Clues Tell Us About Tomorrow (University of California Press, Spring 2013) we present evidence for similar if not larger floods that have occurred every one to two centuries over the past two millennia in California, as well as nature’s flip-side: deep and prolonged droughts.