El Niño supplied portions of Northern California with more than 100 days of precipitation, 30-50 days in the northern Sierra and Central Coast, 40-50 days in the Bay Area and 10-40 days in Southern California since October 1, 2015. Winter storms also reduced the drought by 9.02 percent since March 1, according to the U.S. Drought Monitor, in areas of severe, extreme and exceptional drought, otherwise referred to as D2-D4 areas.
Since October 1, statewide D2-D4 drought areas have reduced by 18.72 percent.
“Obviously, there is a large gradient from north to south with the biggest winners northwest and north-central portions of the state or more generally Northern California has benefitted more than Southern California,” said David Simeral, Associate Research Meteorologist for the U.S. Drought Monitor.
El Niño was expected to weaken with the official arrival of spring on March 20, though climate forecasters from National Oceanic and Atmospheric Administration (NOAA) foresee conditions remaining intact and possibly shaping spring forecasts.
Above-average precipitation is likely across western Alaska and the southern half of the country including most of California, the Southwest, the Gulf Coast and the Southeast from April through June, according to NOAA. Conversely, the Great Lakes, parts of the Pacific Northwest, the southern Alaska Panhandle and Hawaii should receive below-average precipitation.
Temperatures also are expected to be above-average for most of the country aside from the Central and Southern Plains.
“The water resources conditions in California are more favorable than they’ve been since 2011,” said NOAA hydrologist Rob Hartman of the California Nevada River Forecast Center during a press conference. “The last two weeks have really gone a long ways towards brightening that picture with some significant winter storms that have arrived primarily to Northern California over that period.”
Areas of the country still under water from torrential rainfall earlier this month have an elevated risk of moderate flooding, according to NOAA’s U.S. 2016 Spring Climate and Flood Outlook released on March 17.
“Our assessment of spring flood risk is based in large part on saturated soils and elevated streamflows from the Gulf Coast northward along the Mississippi River, although heavy rainfall at any time can cause local or regional flooding, even in places where the risk is currently considered low,” said Tom Graziano, acting director of NOAA’s National Water Center. “We encourage people to be prepared for the range of spring weather threats, including flooding, and tune into local forecasts to monitor their personal risk.”
California is in the midst of an ongoing historic drought of four-plus years, and extreme and exceptional drought conditions still exist in the majority of the state. NOAA detailed that snowmelt and rain improved drought conditions in Northern California, but the rest of the state witnessed only a small benefit from recent precipitation fueled by a near-record El Niño.
“There’s been a lot of discussion and speculation about what it would take to end the drought in California,” Hartman said. “Over the last four years we’ve dug a very deep hole missing in total between 1-2 years of precipitation and there’s been substantial groundwater pumping overdrafts throughout that period that’s really been quite a hit on the overall environment.”
As of March 16, Eureka was 137 percent of normal precipitation. Other Northern California cities also had recent increases, primarily because of wet weather in early March.
Redding and Stockton were both at 120 percent of normal precipitation, San Francisco was 94 percent, Sacramento was 90 percent and Oroville was at 87 percent.
In general, conditions are far better in the northern half of the state than the southern.
“As you would expect in a strong El Niño environment as we’ve had this winter you would expect above normal precipitation in Southern California and perhaps a little bit above in Northern California,” Hartman said. “But that hasn’t really been the case with Southern California really lagging in its rainfall throughout the winter period. But Northern California has really benefitted from the system and really has been good.”
Regardless, there is still work to be done to conserve water as the drought lingers. The Department of Water Resources reported that this month’s storms boosted California’s two largest reservoirs – Shasta Lake and Lake Oroville – to their historically average levels for this time of year. Still, other key reservoirs remain critically low, thus the urgency to conserve.
Learn more about how to conserve water here.