Despite precipitation in San Mateo County this rainy season nearly doubling historic averages to this point, the path to full drought recovery remains unclear as the region continues to reel from recent record-breaking dry years.
As of last week, storms since Oct. 1 had dumped 13.7 inches of rain in Redwood City and as much as 18 inches in Half Moon Bay while historic averages for the span are 6.4 and 9.2 inches respectively, according to the National Weather Service. In comparison, by this time last year just 1.5 and 3.1 inches had fallen at those locations.
It’s a trend that’s rung true for much of Northern California, which has been drenched in recent month’s atmospheric river events. In the Sierras, snowpacks are at 130% of average.
But though the precipitation has helped pull much of the state, including the county, from extreme to severe drought classification, according to the National Integrated Drought Information System, officials are warning that between low reservoir levels, parched soil and above average temperatures, the drought is far from over.
“Two wet months won’t make up for what we’ve experienced, which has been some of the driest weather on record and some of the hottest weather on record,” Nicole Sandkulla, CEO of the Bay Area Water Supply and Conservation Agency, said. “We’re still early on in the winter season … we’re waiting to see the rest of the winter and hopefully continue to get some great precipitation.”
Sandkulla pointed to last year’s predictions of snowpack runoff to refill reservoirs — predictions she said turned out to be “all wrong” as water seeped into dry soil or evaporated during abnormal heat. She said given those variables, even in the event of continued strong precipitation, it’s unclear if this season alone could end the state drought.
The Hetch Hetchy reservoir system, responsible for providing water to much of the Bay Area including the Peninsula, remains below historic averages at 76% capacity, according to Sandkulla. While the figure is 28% more than this time last year, normal levels for this time of year are 81%. Statewide, major reservoirs are collectively at around two-thirds of normal levels, according to a Jan. 1 CalMatters estimate based on 25 reservoirs.
“We not only need to have a continuation of wet weather, we also need to have [lower] average temperatures in the winter and spring with the hope that will restore a normal pattern of runoff,” Sandkulla said.
California’s wet season spans through April. While close to 16 inches of snow has accumulated in the state so far, another foot will need to fall before March to meet normal levels. California in 2013 experienced heavy precipitation through January, leading to levels similar to today’s, but a dry remainder of the year put total snowpack around half of normal levels.
This year’s precipitation is affected by a La Niña climate pattern — brought on by cooler-than-usual surface water in parts of the Pacific Ocean. While La Niñas create varying weather globally, historically the phenomena has meant drier conditions in the southern part of the state and wetter conditions in the Pacific Northwest, putting Northern California in a position to go either way.
With a dry start to the month, forecasters from the National Weather Service are predicting clear skies for the Bay Area at least through Monday.
Roughly two-thirds of the state remains in a severe drought, and 16% remain in an extreme drought. In October, 88% of the state was within the extreme drought classification. Severe drought classification entails a longer fire season, stress on trees and plants and inadequate grazing land.
(650) 344-5200, ext. 105