El Niño’s winter storms are no cure-all for California drought

Frank Gehrke, chief of the California Cooperative Snow Surveys Program for the Department of Water Resources, talks to reporters after conducting a snow survey near Echo Summit, Calif., on Tuesday, March 1, 2016.
Frank Gehrke, chief of the California Cooperative Snow Surveys Program for the Department of Water Resources, talks to reporters after conducting a snow survey near Echo Summit, Calif., on Tuesday, March 1, 2016. AP

The El Niño storms drenching California won’t suffice to solve the state’s drought and won’t permanently save the Central Valley’s vulnerable salmon, federal scientists are cautioning.

In an apolitical assessment that comes amid a highly political time, National Oceanic and Atmospheric Administration experts stress that this year’s El Niño bounty is both useful and limited. It might well be followed, moreover, by a swing back to a different kind of weather complication called La Niña.

“Not all water demands are going to be met, 100 percent, by the recovery we’re seeing relative to the last four years,” NOAA research meteorologist Martin Hoerling said Wednesday in a news briefing. “There are systemic issues with water supply that go beyond precipitation in any given year.”

In particular, Hoerling cited a “drawdown in groundwater in many places in the state that’s not sustainable” and must be addressed “as a long-term policy issue.”

The snowpack isn’t able to reach its full potential, because it’s melting earlier.

NOAA physical scientist Sarah Kapnick

The policy issues, in turn, confront distinct political climates in Sacramento, California, and on Capitol Hill, where partisanship, ideological conflict and regional tensions can prevail. Underscoring the uncertainties ahead, Democratic Sen. Barbara Boxer of California remains publicly uncommitted to a comprehensive California water bill unveiled in January and formally introduced a month ago by California Democratic Sen. Dianne Feinstein.

The House of Representatives has passed a sweeping California water bill on several occasions, most recently last July, on a day when the temperature in Fresno hit 100 degrees. All the House bills, though, passed before the onset of the latest El Niño, the 20th or so since record-keeping began around 1895.

“We’ve had a sea of change, if you will, in terms of the vulnerability of California to the ocean conditions,” Hoerling said Wednesday.

Joined by several NOAA colleagues, Hoerling briefed reporters on the latest research into the real-world laboratory conditions spun up by El Niño. For scientists and lawmakers alike, it’s a mixed bag.

El Nino is a cyclical weather pattern associated with a zone of warm water that develops in the Pacific Ocean. Its counterpart, La Nina, is associated with a band of unusually cold Pacific Ocean water.

Precipitation is way up this year, exceeding 100 percent of the average at measuring sites in places such as Placerville, Mariposa County’s Exchequer Dam and the Tulare County town of Lemon Cove, among other locations.

The Sierra Nevada’s snowpack is consequently much better than in recent years, but still below average and vulnerable to early melting. Depleted groundwater is unlikely to fully rebound. Enhanced river flows will help salmon that require cold water, but other factors still threaten fish health.

83 Percentage of normal for this time of year for the Sierra Nevada’s snowpack as of Wednesday

“Not all drought conditions are going to recover, regardless of how much additional (precipitation) we get,” Hoerling said.

Statewide, the Sierra snow water equivalent as of Wednesday was 83 percent of normal for this time of year. The snowpack is deepest in the central Sierra Nevada, where it is 87 percent of average, and slightest in the southern part of the mountain range, where it is 78 percent of average.

While that’s an improvement over recent years, scientists said the snowpack depth and distribution were not as favorable for Southern California’s water supply as those from El Niños in 1982-83 and 1997-98.

“El Niños have very different types of flavors,” NOAA physical scientist Sarah Kapnick said, adding that “there’s been more precipitation in the north than there has been in the past. If that were directed more southerly, we’d have more snowpack.”

Ominously, Kapnick added that while snowpack melting typically begins in April, this year’s has begun already.

Scientists expect the El Niño to subside by late spring or early summer; after which, Hoerling said, “the odds are certainly pushed” in the direction of a possible La Niña effect in the following year, with uncertain consequences for when and where precipitation falls next.

Michael Doyle: 202-383-0006, @MichaelDoyle10