SIERRA SNOWPACK BELOW NORMAL LEVELS; OFFICIALS SAY IT'S NO SURE SIGN OF DRY WINTER.

Byline: Deborah Sullivan Daily News Staff Writer

Snowpack levels in the Sierra Nevada are lower than average for the year to date, but officials say it's too early to tell whether they foretell a dry winter.

Snowpack core samples tested Tuesday in the northern Sierra show water content at 91 percent to 96 percent of normal levels, said Jeff Cohen, spokesman for the California Department of Water Resources.

Statewide measurements show the California average to be 75 percent of normal for the year to date and snow levels south of Yosemite to be only half of normal, said water supply forecaster Pierre Stephens.

Tests by the Los Angeles Department of Water and Power found that its snowpack at Mammoth Pass is at 60 percent of normal, said hydrologic engineer Vee Miller.

Officials said it's uncertain whether the findings are indicative of low water supplies to come, because January and February storms still might drop heavy snows on the Sierra.

``The snowpack varies incredibly from month to month, so right now it's kind of early to be making predictions about whether it's going to be a dry year,'' Miller said. ``Right now we're not too concerned about it. We're just watching the trends.''

James Murakami, a staff meteorologist with the Atmospheric Sciences Department at the University of California, Los Angeles, said the low snowpack could be related to dry weather associated with La Nina, the weather trend that follows wet El Nino years.

``Statistically with La Nina seasons, at least in Southern California, seven out of eight La Nina events tend to be on the dry side, lower than normal, and even that eighth season, statistically, it's barely above normal,'' he said.

However, he added, that correlation between dry weather and La Nina is weaker in Central and Northern California, where most snowfall occurs.

Officials said there's still the possibility of normal snowfall.

``There have been years when we have gone up to the snow survey course for this measurement and it's been dry, then January comes knocking, and we have a couple big storms and it's bigger than average,'' Cohen said.

Furthermore, water officials said, the preceding wet years have boosted the city's water supplies sufficiently to avoid any shortages if there is low snowmelt.

The Metropolitan Water District, which supplies water to the DWP and other local districts throughout Southern California, said it should not be vulnerable in the event of a dry year, said spokesman Rob Hallwachs.

Its supplies come from from the State Water Project in the northern Sierra, which has received close to normal snowmelt levels this year, and from the Colorado River, which has large enough reservoirs to compensate for low snowmelt.

Miller said DWP reservoirs in the Sierra still are full from last year's El Nino-driven storms, as is its groundwater table in the San Fernando Valley. If this year's snowmelt proves inadequate, he said, the city can increase pumping and buy more water from the MWD.