Country

Please choose your default site

Americas

Asia

Europe

News
The snowpack in the mountain range this spring was just 5 percent of the average in the second half of the 20th century and scientists said the findings indicated "the 2015 low is unprecedented in the context of the past 500 years."

Sierra Nevada snowpack estimated at 500-year low


Saturday, September 19, 2015, 2:00 - (Reuters) - The snowpack in California's Sierra Nevada mountains probably shrank to the lowest in 500 years this year and climate change may cause further declines, worsening water shortages in the drought-stricken state, a U.S. study said on Monday.

The snowpack in the mountain range this spring was just 5 percent of the average in the second half of the 20th century and scientists said the findings indicated "the 2015 low is unprecedented in the context of the past 500 years." 

The low was based on records of snowfall and temperatures inferred from annual growth rings of blue oaks and other trees, meaning some uncertainties about extremes in past centuries. 

The record low was an "ominous sign" of the severity of a record drought in the state since 2012 that is affecting everything from agriculture to hydropower generation, the scientists wrote in the journal Nature Climate Change. 


RELATED: El Niño Contributes to a Tale of Two Winter Seasons. Here's a sneak peek at Winter 2015-16


On Sunday, California governor Jerry Brown declared a state of emergency in two counties where wildfires have destroyed hundreds of homes and forced thousands of residents to flee. 

"Sierra Nevada snowpack plays a critical role in replenishing the state's water reservoirs and provides 30 percent of its water supply," according to the study, led by the University of Arizona. 

Global warming was projected to "further increase the probability of severe drought events," they wrote.

Spatial distribution of the total volume of water in the snowpack across the Tuolumne River Basin on March 25, 2015 (bottom) and April 7, 2014 (top) as measured by NASA's Airborne Snow Observatory. Credits: NASA/JPL-Caltech

Valerie Trouet, one of the authors at the University of Arizona, told Reuters there were reasons to believe that man-made warming "played an important role in the 2015 snowpack low" even though such extremes may be just freak natural events. 


The Weather Network releases it's 2015 US Fall Forecast: See what the next three months have in store!


The scientists also said the uncertainties in Monday's tree ring data indicated that a few years, mainly in the 16th century, might have had snowpack lows even lower than the 2015 numbers. 

The study found that the depth of snow at 108 measuring stations in the Sierra Nevada on April 1 was just 5.75 cm (2.3 inches) in "snow water equivalent" - the depth of the water if the snow melted - against an average 69.8 cm from 1930-2014. 


Snows are retreating in many parts of the world because of higher temperatures, blamed by a U.N. panel of climate experts on rising emissions from burning fossil fuels. 

They say warming is causing more heatwaves, downpours and rising sea levels. Since 1955, the U.S.

Deficit in the total volume of water contained within the Tuolumne River Basin snowpack from this time in 2014 to now. The deeper the red color, the greater the volume of water lost. Credits: NASA/JPL-Caltech

Environmental Protection Agency says that April snowpack has declined on average by about 23 percent at measuring sites across the western United States.

Firefighters make headway against California wildfire
California farmers fight for constitutional right to water
El Niño's warm weather brings strange sea creatures to shore

Leave a Comment

What do you think? Join the conversation.
Default saved
Close

Search Location

Close