California droughts can last decades … or even centuries. As the San Jose Mercury News points out:
Through studies of tree rings, sediment and other natural evidence, researchers have documented multiple droughts in California that lasted 10 or 20 years in a row during the past 1,000 years — compared to the mere three-year duration of the current dry spell. The two most severe megadroughts make the Dust Bowl of the 1930s look tame: a 240-year-long drought that started in 850 and, 50 years after the conclusion of that one, another that stretched at least 180 years.
“We continue to run California as if the longest drought we are ever going to encounter is about seven years,” said Scott Stine, a professor of geography and environmental studies at Cal State East Bay. “We’re living in a dream world.”
Some scientists believe we are already in a megadrought, although that view is not universally accepted.
Bill Patzert, a research scientist and oceanographer at NASA’s Jet Propulsion Laboratory in Pasadena, says that the West is in a 20-year drought that began in 2000. He cites the fact that a phenomenon known as a “negative Pacific decadal oscillation” [not linked to climate change] is underway — and that historically has been linked to extreme high-pressure ridges that block storms.
We are not forecasting gloom and doom. Hopefully, the West Coast will soon get enough rain to end the drought.