Tag Archive: Sierra Nevada


Police officers Eric Baade, left, and Daren Prociw ride across the bed of Folsom Lake.

Researchers have documented multiple droughts in California that lasted 10 or 20 years in a row during the past 1,000 years.

SAN JOSE, Calif. — California’s current drought is being billed as the driest period in the state’s recorded rainfall history. But scientists who study the West’s long-term climate patterns say the state has been parched for much longer stretches before that 163-year historical period began.

And they worry that the “megadroughts” typical of California’s earlier history could come again.

Related: California says it won’t be able to fill water demand

Through studies of tree rings, sediment and other natural evidence, researchers have documented multiple droughts in California that lasted 10 or 20 years in a row during the past 1,000 years — compared to the mere three-year duration of the current dry spell. The two most severe megadroughts make the Dust Bowl of the 1930s look tame: a 240-year-long drought that started in 850 and, 50 years after the conclusion of that one, another that stretched at least 180 years.

“We continue to run California as if the longest drought we are ever going to encounter is about seven years,” said Scott Stine, a professor of geography and environmental studies at Cal State East Bay. “We’re living in a dream world.”

California in 2013 received less rain than in any year since it became a state in 1850. And at least one Bay Area scientist says that based on tree ring data, the current rainfall season is on pace to be the driest since 1580 — more than 150 years before George Washington was born. The question is: How much longer will it last?

A megadrought today would have catastrophic effects.

California, the nation’s most populous state with 38 million residents, has built a massive economy, Silicon Valley, Hollywood and millions of acres of farmland, all in a semiarid area. The state’s dams, canals and reservoirs have never been tested by the kind of prolonged drought that experts say will almost certainly occur again.

Related: Water war fought underground

Stine, who has spent decades studying tree stumps in Mono Lake, Tenaya Lake, the Walker River and other parts of the Sierra Nevada, said that the past century has been among the wettest of the last 7,000 years.

Looking back, the long-term record also shows some staggeringly wet periods. The decades between the two medieval megadroughts, for example, delivered years of above-normal rainfall — the kind that would cause devastating floods today.

The longest droughts of the 20th century, what Californians think of as severe, occurred from 1987 to 1992 and from 1928 to 1934. Both, Stine said, are minor compared to the ancient droughts of 850 to 1090 and 1140 to 1320.

What would happen if the current drought continued for another 10 years or more?

Without question, longtime water experts say, farmers would bear the brunt. Cities would suffer but adapt.

The reason: Although many Californians think that population growth is the main driver of water demand statewide, it actually is agriculture. In an average year, farmers use 80 percent of the water consumed by people and businesses — 34 million of 43 million acre-feet diverted from rivers, lakes and groundwater, according to the state Department of Water Resources.

“Cities would be inconvenienced greatly and suffer some. Smaller cities would get it worse, but farmers would take the biggest hit,” said Maurice Roos, the department’s chief hydrologist. “Cities can always afford to spend a lot of money to buy what water is left.”

Roos, who has worked at the department since 1957, said the prospect of megadroughts is another reason to build more storage — both underground and in reservoirs — to catch rain in wet years.

In a megadrought, there would be much less water in the Delta to pump. Farmers’ allotments would shrink to nothing. Large reservoirs like Shasta, Oroville and San Luis would eventually go dry after five or more years of little or no rain.

Farmers would fallow millions of acres, letting row crops die first. They’d pump massive amounts of groundwater to keep orchards alive, but eventually those wells would go dry. And although deeper wells could be dug, the costs could exceed the value of their crops. Banks would refuse to loan the farmers money.

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By Anthony Sagliani, Meteorologist
January 30, 2014; 5:38 AM
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As severe to extreme drought continues to grip much of California, the first significant storm since early December is bearing down upon the state.

A persistent ridge of high pressure that has been stationed over the western United States for the last several months has crumbled during the past couple of days.

This has allowed a storm track that had been sending storms into far northern Canada to dive southward, right into the Pacific Northwest and California.

While the widespread sunshine and warmth of the last few weeks may be over for now, the change in weather is marked by very beneficial, drought-easing rain and snow, especially in the Sierra Nevada mountains.

Elevations above 8,000 feet can expect snowfall amounts to exceed at least 2 feet through Friday evening. Winds will gust over 90 mph across the higher ridges.

Lower elevations, such as Lake Tahoe, can expect snowfall amounts to range from 6-12 inches through Friday.

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Driest California in 500 Years?

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Driest California in 500 Years?

SAN FRANCISCO—Weird things are happening in California. Bears, normally hibernating at this time of year, have climbed out of their caves to search for food. Some visitors to Tahoe are renting bikes, not skis.

As the East Coast digs out from its latest snow dump, Californians can only look on enviously. Here, the snowpack in the Sierra Nevada Mountains, the state’s great water-supply source, stands at a scary 13 percent of normal. California suffered its driest year on record in 2013, but what’s yet to come is even more terrifying. Federal forecasters predict that the drought will continue or intensify through at least April—by which time, the “rainy” season will be over.

The Golden State should probably be panicking more than it is. Reservoir levels are falling, but only a few cities, including Sacramento and the Sonoma County town of Healdsburg, have mandated water-use reductions. Both have instituted cuts on the order of 20 percent for every household. Governor Jerry Brown has asked everyone to make voluntary cuts, but as drought-stricken Midland, Texas, learned a few years ago, voluntary never quite does it. (An only-in-California water-saving tip I’ve seen: go around in the buff, to save on the need to wash clothes.)

The problem is a huge atmospheric ridge of high-pressure that’s been hovering off the coast for an unprecedented 13 months. Storms can’t break through, so they go around and over it. The really worrying part, as the Christian Science Monitor explained this week, is that the longer the ridge hangs around, the sturdier it gets. Nobody knows when it will disband. (And no, we also don’t yet know if all this is linked to climate change, but California will doubtless be glad to trumpet a connection.)

“This could potentially be the driest water year in 500 years,” says B. Lynn Ingram, a University of California at Berkeley paleoclimatologist.

Assuming the drought continues, it’s going to have huge and complex effects. Among them:

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Spaceweather.com

SPACE WEATHER BALLOON UPDATE:

by Dr. Tony Phillips.

The payload of a space weather balloon launched Jan. 8th by the students of Earth to Sky Calculus has been recovered from its landing site in Death Valley National Park. The purpose of the flight was to study a solar radiation storm in progress at the time of the launch. Analyzing the data may take a few days. Meanwhile, here is the view from the stratosphere:

These pictures were taken by a pair of Hero3+ cameras looking out of the payload capsule. The upper frame shows the Sierra Nevada mountain range, unusually brown for this time of year as California endures a historic drought. The lower frame captures the balloon popping at an altitude of approximately 100,000 feet. Click on each frame for a closer look. The landscape shot was made using the Hero3+’s new “superview mode”–a favorite of snowboarders and now, for the first time, balloonists!

In addition to cameras, the payload contained an x-ray/gamma-ray dosimeter, a GPS altimeter, and a cryogenic thermometer. Together these instruments can form a complete thermal and radiation profile of the atmosphere throughout the flight. The students plan to pay special attention to data collected at aviation altitudes to learn how much radiation air travelers absorb during periods of high solar activity.

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By Ari Phillips on October 31, 2013 at 10:08 am

A Sierra Nevada reservoir.

A Sierra Nevada reservoir.

CREDIT: Shutterstock: Katarish

California is known for its massive water infrastructure in which northern reservoirs, which fill up from the Sierra Nevada snowpack, supply the populous southern and coastal regions of the state. However going into a third year of dry winter conditions, many of these northern man-made oases are at precariously low levels, hovering between one-third and one-half capacity, far less than the average for October.

More than 20 million Californians and many farmers in the state’s crop-intensive Central Valley depend on northern reservoirs for their water.

“Both the State Water Project and federal Central Valley Project heavily depend on the Sierra Nevada snowpack,” Mark Cowin, director of the state Department of Water Resources, told The Fresno Bee. “We are now facing real trouble if 2014 is dry.”

Cowin said that dwindling reservoirs should be a wake-up call to Californians, and indicate that it’s time to prepare for additional water-conservation measures.

Pete Lucero of the U.S. Bureau of Reclamation, owner of the Central Valley Project, told the Fresno Bee that January through May 2013 were California’s driest in about 90 years of recordkeeping.

Currently the San Luis Reservoir, which gets water from the Sacramento-San Joaquin River Delta, is only 22 percent of its historical average for this time of year.

At a recent workshop that brought together leaders to hear about California’s water challenges, Cowin said that decades of disagreement among environmentalists, farmers, water agencies, and other interests in various parts of California has “resulted in gridlock.” And that with “environmental laws, climate change, and population growth intensifying the conflict, there’s simply no time to waste.”

 

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Climate change is taking a visible toll on Yosemite National Park, where the largest ice mass in the park is in a death spiral, geologists say.

During an annual trek to the glacier deep in Yosemite’s backcountry last month, Greg Stock, the park’s first full-time geologist, found that Lyell Glacier had shrunk visibly since his visit last year, continuing a trend that began more than a century ago.

Lyell has dropped 62% of its mass and lost 120 vertical feet of ice over the last 100 years. “We give it 20 years or so of existence — then it’ll vanish, leaving behind rocky debris,” Stock said.

The Sierra Nevada Mountains have roughly 100 remaining glaciers, two of them in Yosemite. The shrinkage of glaciers across the Sierra is also occurring around the world. Great ice sheets are dwindling, prompting concerns about what happens next to surrounding ecological systems after perennial rivulets of melted ice disappear.

“We’ve looked at glaciers in California, Colorado, Wyoming, Washington and elsewhere, and they’re all thinning because of warming temperatures and less precipitation,” said Andrew Fountain, professor of geology and geography at Portland State University in Oregon. “This is the beginning of the end of these things.”

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WATER WORLD

by Staff Writers
Irvine CA (SPX) Feb 04, 2013


File image.

Agricultural irrigation in California’s Central Valley doubles the amount of water vapor pumped into the atmosphere, ratcheting up rainfall and powerful monsoons across the interior Southwest, according to a new study by UC Irvine scientists.

Moisture on the vast farm fields evaporates, is blown over the Sierra Nevada and dumps 15 percent more than average summer rain in numerous other states. Runoff to the Colorado River increases by 28 percent, and the Four Corners region experiences a 56 percent boost in runoff. While the additional water supply can be a good thing, the transport pattern also accelerates the severity of monsoons and other potentially destructive seasonal weather events.

“If we stop irrigating in the Valley, we’ll see a decrease in stream flow in the Colorado River basin,” said climate hydrologist Jay Famiglietti, senior author on the paper, which will be published online in the journal Geophysical Research Letters.

 

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Earth Watch Report  –  Extreme Weather

 

CLIMATE SCIENCE

Dry spell projected for southwest US

by Staff Writers
Paris (AFP)

Southwestern areas of the United States, reeling from its worst drought in 50 years, may have 10 percent less surface water within a decade due to global warming, a study said Sunday.

While rainfall is forecast to increase over northern California in winter and the Colorado River feeding area, warmer temperatures will outstrip these gains by speeding up evaporation, leaving the soil and rivers drier, a research paper said.

Texas will likely be dealt a double blow with declining rainfall and an increase in evaporation, said the paper based on weather simulations and published in Nature Climate Change.

Overall for the area, “annual mean runoff in 2021-2040 is projected to be 10 percent less than in the second half of the 20th century,” co-author Richard Seager of Columbia University told AFP.

This “is a very significant decline given the stress on Colorado River-based water resources” for agriculture and household use, he added.

Runoff is rainfall not absorbed by the soil, running overland or in rivers.

According to the paper, California obtains most of its water from snow on the Sierra Nevada mountain range, while the Colorado River is fed from tributaries created by melting winter snowfall and summer rainfall.

The river provides water to seven US states and Mexico.

Texas, for its part, uses water from rivers and groundwater within its own borders, said the paper.

Average annual runoff for the region overall should drop by about 10 percent, and about 25 percent in spring for the Colorado tributary headwaters.

“Drying intensifies as the century advances,” added the paper.

“These projected declines in surface-water availability for the coming two decades are probably of sufficient amplitude to place additional stress on regional water resources.”

 

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Winter storm Brutus threatens snow, severe weather for US West, Midwest

Weather.com

© Weather.com

This time, not only will there be a wind-snow combo on the cold side of the system, but there will be a warm sector with severe weather potential – eventually.

But first things first.

Wintry Side: Snow, Wind, Blizzard?

With strong low pressure developing over the northern Rockies and a strong high pressure zone to the north over western Canada, the stage is set for a wind-driven snow.

That snow will develop over Montana and central Idaho on Thursday. There will also be snow farther west over the Oregon Cascades and the northern Sierra Nevada in California.

The worst conditions are expected over parts of northern Montana, where blizzard warnings are in effect from Thursday morning through early Saturday morning – a long period of dangerous travel conditions. Winter storm warnings cover much of western and central Montana, including the Interstate 15 and Interstate 90 corridors.

By Friday, this snow expands south into the central and perhaps even southern Sierra. The mountains of Utah, and potentially western Colorado as well, should get in on the snow by the end of Friday.

Friday night into Saturday, the snow and wind will expand east into eastern Montana and North Dakota. Gusty winds will whip this snow sideways across the open prairie, leading to potential near-blizzard conditions along Interstate 94.

Some locations in Montana and North Dakota will likely see well over a foot of snow from this storm system.

Severe Side: Saturday Storms

As the storm system starts to emerge into the Plains and Midwestern states this weekend, it will encounter a tongue of unseasonably warm, moist air from the Gulf of Mexico reaching all the way north into the upper Mississippi Valley.

The strong cold front will push east into this unstable air and a powerful jet stream will supply plenty of energy in the upper atmosphere.

The likely result? Thunderstorms, some of which could turn severe Saturday along the Interstate 35 corridor from Minneapolis to Dallas.

It appears that the most likely mode for severe weather would be one or more squall lines of thunderstorms with damaging winds.

(MORE: Severe weather tracker)

Crossroads News : Changes In The World Around Us And Our Place In It

Environmental

climate change and  wildlife

Studies shed light on why species stay or go in response to climate change

by Staff Writers
Berkeley CA (SPX)


The Belding’s ground squirrel has disappeared from 42 percent of the sites in the California mountains where they were recorded in the early 1900s, but noted that some human-modified areas provided an artificial oasis for the squirrel. (Toni Lyn Morelli photo)

Two new studies by scientists at UC Berkeley provide a clearer picture of why some species move in response to climate change, and where they go. One study, published online in the journal Global Change Biology, finds that changes in precipitation have been underappreciated as a factor in driving bird species out of their normal range.

In the other study, published the journal Proceedings of the Royal Society B, researchers found a sharp decrease in range for the Belding’s ground squirrel, but noted some surprising areas where the species found refuge.

The two studies exemplify the type of research being explored through the Berkeley Initiative in Global Change Biology, or BiGCB, an ambitious effort to better understand and predict how plants and animals will respond to changing environmental conditions by studying how they have responded to earlier periods of climate change.

The first study’s findings challenge the conventional reliance on temperature as the only climate-related force impacting where species live. The authors noted that as many as 25 percent of species have shifted in directions that were not predicted in response to temperature changes, yet few attempts have been made to investigate this.

“Our results redefine the fundamental model of how species should respond to future climate change,” said study lead author Morgan Tingley, who began the research as a graduate student in UC Berkeley’s Department of Environmental Science, Policy and Management. “We find that precipitation changes can have a major, opposing influence to temperature in a species’ range shift. Climate change may actually be tearing communities of organisms apart.”

The findings are based upon data gathered from the Grinnell Resurvey Project, which retraces the steps of Joseph Grinnell, founder of the UC Berkeley Museum of Vertebrate Zoology, in his surveys of Sierra Nevada wildlife from the early 1900s. The resurvey project, which began in 2003, was led by Craig Moritz, former UC Berkeley professor of integrative biology, and his colleagues at the Museum of Vertebrate Zoology.

For the bird study, the researchers included 99 species in 77 historic survey sites in Lassen Volcanic, Yosemite and Sequoia national parks, as well as in several national forests. In the century that has passed since the original Grinnell survey, summer and winter temperatures have increased an average of 1-2 degrees Celsius in the Sierra Nevada. Yosemite experienced the most warming – with average temperatures increasing by 3 degrees Celsius – while parts of Lassen actually got cooler and much wetter.

Among the bird species that moved upslope are the Savannah Sparrow, which shifted upward by 2,503 meters, and other meadow species such as the Red-winged Blackbird and Western Meadowlark. The ones that shifted their range downslope include both low-elevation species like the Ash-throated Flycatcher and Western Scrub-Jay, and high-elevation species like the Cassin’s Finch and Red-breasted Nuthatch.

“Temperature did not explain the majority of these shifts,” said Tingley, who is now a postdoctoral researcher at Princeton University’s Program in Science, Technology and Environmental Policy. “Only when we included precipitation as an explanatory variable did our models adequately explain the movement patterns we observed.”

The researchers found that while rising temperatures tended to push birds to cooler regions upslope, increased precipitation, which is more common at higher elevations, pulled them downslope.

“We believe many species may feel this divergent pressure from temperature and precipitation, and in the end, only one wins,” said Tingley.

Notably, more than half of the bird species in each of the three study regions did not shift their range despite pressures from climate change. “Moving is a sign of adaptation, which is good from a conservation standpoint,” said Tingley.

“More worrisome are the species that have not shifted. How are they adapting? Are they moving, but we just can’t detect it? Or are they slowly declining as environmental conditions gradually become less ideal where they live?”

The answers are complex, as illustrated by the second UC Berkeley paper about range changes for a species of squirrel found in the mountains of the western United States.

In that paper, researchers again used information obtained from the Grinnell Resurvey Project. Through visual observations and trapping surveys conducted throughout the mountains of California, they discovered that the Belding’s ground squirrel had disappeared from 42 percent of the sites where they were recorded in the early 1900s. Extinctions were particularly common at sites with high average winter temperatures and large increases in precipitation over the last century.

“We were surprised to see such a dramatic decline in this species, which is well-known to Sierran hikers and was thought to be fairly common,” said study lead author Toni Lyn Morelli, a former National Science Foundation postdoctoral researcher who was based at UC Berkeley. “In fact, the rate of decline is much greater than that seen in the same region for the pika, a small mountain-dwelling cousin of the rabbit that has become the poster child for the effects of climate warming in the contiguous United States.”

Morelli added that the squirrels are thriving in areas that have been modified by humans. For example, irrigated Mono Lake County Park serves as an artificial oasis that sustains squirrel populations despite otherwise hot and dry conditions in eastern California.

“As predictions indicate that the range of the Belding’s ground squirrel could disappear out of California by the end of the century, these areas might be particularly important for this and other climate-impacted species,” said Morelli, who is now a technical advisor for the U.S. Forest Service’s International Programs in the Democratic Republic of Congo.

Although the Belding’s ground squirrel is widespread, the rapid decline in its distribution is of concern because it is an important source of food for raptors and carnivores. However, the paper suggests that even when climate change causes large range declines, some species can persist in human-modified areas.

“Taken together, these two studies indicate that many species have been responding to recent climate change, yet the complexities of a species’ ecological needs and their responses to habitat modification by humans can result in unanticipated responses,” said Steven Beissinger, professor at UC Berkeley’s Department of Environmental Science, Policy and Management and the senior author on both studies. “This makes it very challenging for scientists to project how species will respond to future climate change.”

Funding from the National Science Foundation, National Park Service, and California Landscape Conservation Cooperative helped support this research.

 

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