Sierra Nevada


A Little Lake Reveals Clues About Past Megadroughts

Scientists stumbled on Fallen Leaf Lake and the ancient trees under its surface

Scientists found important climate clues hidden away under Fallen Leaf Lake, just south of Lake Tahoe.

Graham Kent wasn’t researching megadroughts when he and a team of scientists began studying Fallen Leaf Lake, just south of Lake Tahoe. They were mapping faults. The little lake is a good place to study West Tahoe Fault, which cuts right through it.

“Little did we know it was a natural lab for droughts, as well,” Kent, director of the Nevada Seismological Lab at University of Nevada, Reno, told me over the phone. “So what started out as a seismic hazard endeavor became both a seismic hazard and climate study.”

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The Case of the Disappearing Sierra Snowfall

A new report says snowfall in the Sierra hasn’t shrunk, but not everyone’s buying it

Snow has been sparse in the Sierra Nevada this winter.

There are good years and there are bad years, but overall, snowfall in the Sierra hasn’t declined in the past century. That’s according to a new study by University of Alabama climatologist John Christy (who, it’s worth noting, has come under fire as a climate change denier).

The San Francisco Chronicle had a story about the report, “Searching for information in 133 years of California snowfall observations,” (link is to the abstract; full article is behind a pay wall) in today’s paper:

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Snow Survey May Portend a Dry 2013

Skimpy Sierra snowpack may take a while to show up in water supplies

snow Tahoe Sierra California water

After a record dry December, there's finally snow on the ground near Soda Springs, at Lake Tahoe.

This morning’s snow survey (PDF) didn’t turn up any big surprises. As remote sensors foreshadowed, water content in the Sierra snowpack is 37% of normal for this time of year, and less than a quarter of the average for April, which is when the snowpack is usually at its peak before it begins melting and filling up California’s reservoirs.

What’s worrisome about that, according to Jeanine Jones, Interstate Resources Manager at the Department of Water Resources, is that about half of California’s annual precipitation typically falls between December and February, months that are mostly already behind us. “So where we are this year is: November was dry, December was close to record dry, January was maybe half of average,” Jones told me. “And currently the forecast for the first  ten days or so of February is essentially dry.” Continue reading

Tioga Pass Unwrapped: A Rare Midwinter Glimpse of “The Roof of California”

Authorities finally closed California’s highest mountain pass this week. Right before they did, Climate Watch contributor Dan Brekke got to see what few of us glimpse this time of year.

Highway 120 in Yosemite National Park winds toward Tioga Pass. The road closed Tuesday night after its longest winter opening since at least 1933.

It first captivated me back when I was an adolescent map reader back in the Midwest. I was poring over maps of California for a trip that didn’t happen—then—and took note of the roads across the Sierra Nevada. And the highest of all the mountain routes I could see crossed Tioga Pass, at an altitude that rounds to 10,000 feet. Nearly two miles above sea level.

Eventually I took that trip to California, but it was still a long time before I actually saw the place the map depicted. A good 15 years or so after I moved out here, I managed to scramble up there on a long weekend and spent a single afternoon driving Highway 120, the Tioga Road. Continue reading

We’re Not Alone: Wimpy Winter Weather Across the Country

Some atmospheric scientists think that could change soon.

By Andrew Freedman

While some may be cheering the lack of snow as welcome relief, the widespread lack of it spells trouble for the ski industry, which pumps billions into the wintertime economy in states from California to Maine, and requires cooperation from Mother Nature to stay in business.

Snow from last year's big winter storms could still be seen on the mountains near Lake Tahoe on August 30th. This winter has been one of the driest on record.

Ski area operators across the country are already reporting drops in lift ticket sales, and are hoping for a major change in the weather pattern to bring colder, snowier weather. So far, die-hard skiers have been forced to either ski on man-made snow or travel to one of the few far-flung areas that have benefited from the unusual weather, such as the mountains of New Mexico or Alaska (where one town has had 18 feet of snow).

Compared to last winter, this wimpy winter weather is coming as quite a shock.

Snow was so widespread last winter that at one point in January, every state except Florida had some snow on the ground. But this year, the U.S. had the 11th least extensive December snow cover in the 46-year satellite record, said David Robinson, the director of the Global Snow Lab at Rutgers University.

“Is it fair to call it a snow drought? We’re getting there,” Robinson said. “It’s certainly an early season snow drought.”

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American Pika Gets Another Shot at Endangered Status

The American pika can only survive within a narrow temperature band and can suffer heat stroke at temperatures as mild as 80 degrees.

The California Fish and Game Commission is asking for public input on the status of the American pika. The small, alpine mammal has been at the center of a prolonged debate over whether to list it under the Endangered Species Act. If the pika ultimately wins endangered status it would be the first species to do so with climate change cited as a major factor contributing to its decline. The Center for Biological Diversity originally petitioned for the pika to receive protected status, considering it to be a bellwether for climate change in California. Continue reading

Sierra Snow Outlook is Bleak

Water users may be relying heavily on leftover water storage from last year

Hard to imagine now: A snowed-over road near Lake Tahoe in March.

It was startling to see the state’s lead snow surveyor kneeling on bare grass near Echo Summit, trying to find enough snow to measure the water content. But so it went with the first official survey of the season, conducted by California’s Dept. of Water Resources.

The manual survey affirmed what remote sensors had already relayed — that water content in the Sierra snowpack stands at just 19% of the average reading for this time, right around New Year’s. The readings are just seven percent of where things usually stand on April first, meaning we have a long way to go, to get back to “normal.” Continue reading

Can Giant Sequoias Survive the Future?

Fragile seedlings are highly vulnerable to drought

Hear my companion radio feature on The California Report weekly magazine.

Giant sequoias naturally grow only on the western slope of the Sierra Nevada.

When William Tweed talks about giant sequoias, he doesn’t beat around the bush.

“Sequoias capture human interest because they’re the perfect thing,” says the writer, historian, and former National Park Service ranger. “They’re the world’s largest trees. We humans like big stuff. They’re also exceedingly old, and they also charm us because they’re rare. We humans go chasing around for the big, the old, and the rare.”

He says while other parks have charismatic megafauna, like bears, or bison, or elk, Sequoia-Kings Canyon National Park and the other national parks in the Sierra Nevada have charismatic megaflora: the giant sequoia. Continue reading

Snow in Tahoe Already: How Weird is That?

Meteorologists say it’s the shortest Sierra “summer” in four decades

An early snow in the Grouse Lakes area of the Sierra Nevada

By Matthew Green

For months now, I had reserved the second weekend in October for my annual grand finale “summertime” backpacking trip. Culminating an unusually short warm season, this was to be the ceremonial final alpine lake swim, the last mosquito bloodletting until well after next year’s thaw. Which is why, as my partner and I proceeded to pitch our tent in about 10 inches of snow last Friday evening, I couldn’t help but feel I’d been had.

Last week’s storm, which swept across the northern half of California early Wednesday, dumped up to a foot of snow in the Sierra’s high peaks, with accumulation as low as 5,000 feet. According to the Central Sierra Snow Lab, this is the first snowstorm in 96 days – since July 1 – marking the shortest duration between storms in the Sierra since 1969. Continue reading

Taking the Pulse of the Mountains

Federal grant enables major new network of Sierra water sensors

A tree at the Fresno County pilot project adorned with sensors

Researchers at UC Merced are set to open a whole new window on the Sierra Nevada. Using two million dollars from the National Science Foundation, hydrologist Roger Bales and his colleagues can now expand on a pilot project to measure the mountains’ “vital signs.”

Bales says beginning next summer, he, UC Berkeley’s Steven Glaser and their team will start installing a network of 20-to-30 instrument clusters throughout the American River watershed, casting a watchful eye over about 2,000 square kilometers that typically gets snow cover. The instruments record factors that affect the mountain’s hydrology, such as temperature, humidity, soil moisture, stream flow and even how much solar radiation penetrates the tree canopy.

Bales says the pilot phase has taught them how to put together a network of wireless sensors that will endure the extreme alpine conditions and still remain reliable (see Sasha Khokha’s post and slide show from March). Continue reading