By Sharon Bernstein
SACRAMENTO, Calif. (Reuters) - Wet winter storms that dropped up to a foot (30 cm) of rain on parts of California have modestly eased the state's ongoing drought over the past three months, U.S. drought experts said on Thursday.
The portion of California in the most extreme categories of drought has dropped by about 13 percent since mid-November, said Mark Svoboda, a climatologist with the National Drought Mitigation Center at the University of Nebraska.
The relief provided by two so-called atmospheric rivers is far from enough to make more than a dent in California's ongoing dry conditions, which are entering their fourth year.
Part of the reason is that it was relatively warm during the most recent storms, which occurred in early February, leading to rain but not to the snow that is needed in California's Sierra Nevada mountains, which provides drinking water and protection from fire when it melts in the spring.
"We did see a chipping away of the drought," Svoboda said. "The concern now is as we get closer to March is that we don't have a lot of snow."
Still, the relief is measurable in the parched state. Three months ago, 55 percent of California was in the worst category of exceptional drought, compared to 41 percent now. About 80 percent was in the next-to-worst category, extreme drought, compared to 67 percent now, according to the U.S. Drought Monitor, which is published by the Drought Mitigation Center and the U.S. National Oceanic and Atmospheric Administration.
Overall, about 98 percent of California is considered to be in a drought, down from 100 percent three months ago.
Further atmospheric rivers are not forecast for the near-term in California, but two more modest storm systems may hit parts of the state in the next 10 days, said Tom Dang, a meteorologist with the National Weather Service based in Sacramento. The first, which may move into the Sierra Nevada next week, is a weak system but it could bring with it some snow, Dang said.
(Reporting by Sharon Bernstein; Editing by Eric Beech)