Atmospheric River Storms and Megafloods: Past and Present.

Atmospheric river storms are responsible for most of the largest historical floods in California and many western states, as well as megafloods found in the geologic record, that recurred every 100 to 200 years. The only megaflood to strike the American West in recent history occurred during the winter of 1861-62. Although many western states experienced their worst floods on record that year, California bore the brunt of the damage. This deluvial disaster turned enormous regions of California into inland seas for months, and took thousands of human lives. The costs to the state were devastating: one quarter of California's economy was destroyed, forcing the state into bankruptcy.

Today, the same regions that were submerged in 1861-62 are home to California's fastest-growing cities. Although this flood is all but forgotten today, important lessons from this catastrophe can still be learned.

Speaker: Dr. B. Lynn Ingram, UC Berkeley