A rare third year of La Niña is on deck for California, forecasters say. The drought-breaking weather phenomenon was on track to last until May, when tropical storm Isaac formed, and then continued well into November.
Scientists used to be able to look out for La Niña events, which have occurred roughly 5 percent of the time over the past 70 years. This makes the third year-long La Niña event, which began in the eastern pacific island of Hawaii on June 8, the most recent one.
The forecast is not good for California, where rainfall has fallen to near-record lows and farmers are fighting record fires, including the Camp Fire in Butte County. A recent state drought report said that the state likely would not have enough water for this year’s crop and would dry up by the end of the year.
A second La Niña has been in effect since early July, and the third-year event is likely to keep pouring rain on the Central Coast through November, forecasters said.
“We are now on a strong La Niña wave. It will continue through November,” said John Coleman, chief meteorologist for the National Weather Service in Oxnard.
California’s last three years of drought have been the toughest in the state’s history. As of Aug. 24, 2019, a quarter million people and homes have been forced to evacuate from communities around the state.
In the last three years, the state has lost about half its agricultural production and had one in 19 drought days. That’s tied for the second highest drought total in the nation.
The current warm-climate La Niña event is a sign that waters in the Pacific Ocean are returning to normal. The warm waters warm up the ocean’s surface and increase evaporation, which cools the surface of the ocean, a natural mechanism for storing moisture.
“It has a long-term positive effect on California’s precipitation and agriculture because the ocean is a better water source,” Coleman said.
“With the warm pool, you have more evaporation
