Environment & Science

Snowpack dips below average as dry spell hits Nor Cal

The Sierra Nevada snowpack in a typical year provides almost a third of California's water supply.
The Sierra Nevada snowpack in a typical year provides almost a third of California's water supply.
Photo by Anirudh Rao via Flickr Creative

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This year’s El Niño continues to throw curve balls, and here’s the latest: the Sierra Nevada snowpack, which supplies much of California’s water when it melts, fell below average over the weekend.

As of Tuesday it was 91% of average for this time of year. The snowpack hasn’t been that low since the first week of January.

For Southern California, this sort of dry spell has been typical this winter. It rained a decent amount in early January, but storms have mostly stayed away since then.

Things have been much wetter up north until about two weeks ago when dry, warm weather took over that region too.

Michelle Mead with the National Weather Service says don’t panic yet though. Dry spells over the Sierra are common even in El Niño winters.

El Niño Dry Spells

Readings from around Sacramento show that the 1998 El Niño saw nearly 20 consecutive days without snow and a Niño in 1966 saw nearly a month of dry weather.

"We still have the chance for the jet stream or the weather pattern to kick back in to a more El Niño-esque weather pattern," Mead said.

In fact, there is a storm on the way that might help get the snowpack back on track.

Luckily, the dry weather hasn't resulted in too much premature snowpack melt. Mead said.

She said there's been some snow loss below 5,000 feet, but higher elevations have remained mostly frozen.

"It's the snowpack at 7,000 feet and above that really helps supply or resupply the reservoirs in the spring," she said.

As to the mystery of why Southern California is so dry this winter?

Toby Garfield with NOAA's Southwest Fisheries Science Center says to keep in mind that El Niño weather patterns start with water heating up in a a swath of the Pacific Ocean near the equator.

Warming there sets off a chain of climate-related phenomena that result in all sorts of weird weather around the world.

Garfield says this year, the amount of warm water near the equator is much larger than in years past.

"It's probably changed the weather patterns a little bit more than say, we saw in the '98 El Niño," he said.

Garfield says the El Niño signal is still strong and could still be a major force during the rest of Southern California's winter, but nothing is certain.

Much like the snowflakes in the Sierra Nevada snowpack, each El Niño is unique. This one is no exception, he said.

"I would say with each El Niño, we are learning a little bit more about how our weather patterns get influenced," he said.