Sierra Nevada snowpack shrinks

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 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 NASA/JPL Caltech
30 Apr
2015
As California’s record drought continues, snowpack in the Sierra Nevada shrinks

The snowpack in the Tuolumne River Basin in the Sierra Nevada, California contains 40 per cent less water than it did at its highest level in 2014.

NASA data indicates that the water in the snowpack amounts to 74,000 acre-feet or 24billion gallons. At its high-point two years ago, the snowpack covered 179,000 acre-feet. The agency has been using airborne monitoring to check on the snowpack for the last three years.

Tuolumne feeds the irrigation districts and the Hetch Hetchy Regional Water System, which serves San Francisco and nearby settlements. Snowfall accounts for 70 per cent of California’s annual precipitation in normal years, with the ice melting in spring and early summer.

The new research will allow water authorities to provide almost real-time information about how much water will flow from the mountains during California’s ongoing drought.

earth20150401ab-fullSpatial distribution of the total volume of water in the snowpack across the Tuolumne River Basin on 25 March, 2015 (bottom) and 7 April, 2014 (top) as measured by NASA’s Airborne Snow Observatory. (Image: NASA/JPL-Caltech)

‘A mountain’s snowpack is like a giant TV screen, where each pixel in the image varies but blends together with the others to make up a picture,’ says Tom Painter from NASA’s Jet Propulsion Laboratory.

‘For the past century, we’ve estimated mountain snowpack by looking at just a few pixels of the screen – that is, a few sparse ground measurements in each watershed basin. During an intense drought like this one, most of the pixels on the screen are blank – that is, they’re snow-free,’ he adds.

Before the surveys began, the California Department of Water Resources used manual surveys to map snow courses using data from electronic sensors planted in the ground called snow pillows. These are accurate, but sparsely distributed.

Share this story...

Submit to FacebookSubmit to Google PlusSubmit to Twitter

Related items

Geographical Week

Get the best of Geographical delivered straight to your inbox every Friday.

Subscribe Today

Target Ovarian Cancer

EDUCATION PARTNERS

Aberystwyth UniversityUniversity of GreenwichThe University of Winchester

TRAVEL PARTNERS

Ponant

Silversea

Travel the Unknown

DOSSIERS

Like longer reads? Try our in-depth dossiers that provide a comprehensive view of each topic

  • The Nuclear Power Struggle
    The UK appears to be embracing nuclear, a huge U-turn on government policy from just two years ago. Yet this seems to be going against the grain globa...
    The Air That We Breathe
    Cities the world over are struggling to improve air quality as scandals surrounding diesel car emissions come to light and the huge health costs of po...
    Diabetes: The World at Risk
    Diabetes is often thought of as a ‘western’ problem, one linked to the developed world’s overindulgence in fatty foods and chronic lack of physi...
    National Clean Air Day
    For National Clean Air Day, Geographical brings together stories about air pollution and the kind of solutions needed to tackle it ...
    REDD+ or Dead?
    The UN-backed REDD+ (Reducing Emissions from Deforestation and Forest Degradation) scheme, under which developing nations would be paid not to cut dow...

MORE DOSSIERS

NEVER MISS A STORY - follow Geographical

Want to stay up to date with breaking Geographical stories? Join the thousands following us on Twitter, Facebook and Instagram and stay informed about the world.

More articles in PLACES...

Mapping

Where in America can the country's various hate groups be…

Water

The southern US state is sinking twice as fast as…

Cities

An increase in visitors is putting severe strain on Iceland’s…

Cities

Air pollution campaigners hold a disco roadblock, but can it…

Cities

Cities the world over are struggling to improve air quality…

Forests

HSBC has requested a Roundtable on Sustainable Palm Oil investigation…

Mapping

Benjamin Hennig explores visions of a world made bright by humanity

Forests

The EU has asked the European court to authorise an…

Forests

Was last year’s El Niño a practice run for future…

Cities

Far from being separate threats, scientists have found links between…

Mountains

Is the official height of Mount Everest accurate?

Mapping

Where in the world is the highest density of languages?…

Cities

The next stage in autonomous vehicles is hoping to transform…

Mapping

Geographical’s resident data cartographer presents a true picture of the…

Water

What impact could an unprecedented incident of ‘river piracy’ have…

Mountains

Norway is to undercut a mountainous peninsula to create the…

Mapping

Benjmain Hennig explores global mortality with maps

Water

Last winter’s cold conditions contributed a further influx of road…

Water

As one of America’s biggest cities, supplying clean drinking water…

Cities

Cape Town’s Foreshore Freeway Bridge has been left unfinished for…