The National Oceanic and Atmospheric Administration (NOAA) on Thursday released its annual U.S. Winter Outlook, forecasting that an expected El Niño in the Pacific Ocean will increase California’s rain and snow but is unlikely to pull the parched state out of drought.
El Niño is an irregularly occurring climate cycle that is characterized by warm water temperatures in the Pacific and that affects global weather patterns, often leading to increased precipitation across the southern United States.
Although this winter’s El Niño is expected to be one of the strongest on record, NOAA officials said the increased rainfall and snowfall are unlikely to make up for the precipitation California has missed during the last four years of drought.
A NASA study published in July concluded that between 2012 and 2015 California had an accumulated “debt” of 20 inches of precipitation — the average amount of a year's worth of rainfall in the state.
The current dry spell is California’s worst on record. It has led to a shortfall in groundwater levels, damaged ecosystems and billions of dollars in losses for the state’s agricultural industry. Gov. Jerry Brown declared a state of emergency in January 2014.
NOAA officials believe that the probability of El Niño bringing increased precipitation to Southern California is greater than 50 percent. However, Northern California — which is more important to the state in terms of water sources — will only experience 33 percent probability of increased precipitation.
“We can certainly hope for parts of the Sierra in the northern Rockies, because they certainly need it the most, but other than that it’s really hard to make much of a conclusion on snow,” said Mike Halpert, deputy director of NOAA’s Climate Prediction Center.
Paul Ullrich, an assistant professor of regional climate at University of California-Davis, similarly predicted that the state’s upcoming winter season will not add to the snowpack accumulation in the northern Sierras, where much of the state's water has traditionally come from. But he added that the rain would still be welcome.
“This El Niño also seems pretty singular,” Ullrich said. “This is probably the only winter for the next couple years that we can benefit from strong El Niño conditions.”