California braces for major winter storm

Talk about extremes.

After months of record dry and hot conditions, California this week is gearing up for a huge rainstorm that prompted weather officials to issue the state’s first blizzard warning since 2008.

The National Weather Service issued the alert for the northern Sierra Nevada, where 2 to 3 feet of snow were forecast, and for northern communities above 6,000 feet, which were expected to see 10 to 20 inches.

That’s still relatively small compared to California’s most infamous blizzard in 1846, which trapped the Donner Party in the 22-foot Sierra snowstorm.

“Blizzards — they are dangerous,” JPL Climatologist Bill Patzert said.

Making a blizzard

Winds of 35 mph or more combined with heavy snowfall can create a blizzard, which can result in zero visibility whiteout conditions and make traveling treacherous.

In this case, forecasters say, the blizzard warning stems from a low pressure winter storm that is expected to bring with it heavy rain and snow and produce winds as powerful as 80 mph.

“The good news is these north Pacific storms have declared war on the drought,” Patzert said. “This should make us happy.”

The last time the National Weather Service in Sacramento issued a blizzard warning was Jan. 4, 2008, NWS Meteorologist Bill Rasch said. The powerful storm downed trees and power lines, he said.

This time around, several Bay Area school districts closed ahead of the storm as a precaution.

This storm is big

The storm, which has an “atmospheric river” that can be up to 400 miles wide, is twice as strong as last week’s winter storm, which caused havoc in Southern California and trapped more than a dozen people on flooded roadways, Rasch said.

Winds, he said, will drive the storm and intensify rain and snow.

But what is more unusual about this particular storm is the amount of rain expected, especially in Lake Shasta, which could receive 10 inches, said Michael Dettinger, a research hydrologist for the U.S. Geological Survey.

“This is a lot of precipitation for just a couple of days,” he said. “And if it’s cold enough to have snow down to 4,500 feet or so, a lot of that will fall as snow. That means a lot of visibility problems and a lot of snow piling up on the roads and everything else. Should be pretty intense.”

Bring on the snow

Janet Tuttle, owner of Donner Ski Ranch on California 40, welcomes the blizzard after an abysmal last winter season, which was late and began in February.

Unlike other resorts that make their own snow, she relies on Mother Nature to produce snow for her slopes.

“We are quite excited to see this one,” she said. “This time is just about perfect for us.”

In the end, forecasters say the northern Sierra Nevada snowpack will benefit from the storm as it could replenish some water supplies for Sacramento and San Joaquin Valley residents.

“This is really the start of the winter snowpack season,” Patzert said.

veronica.rocha@latimes.com

@VeronicaRochaLA