Our directory of things of interest

University Directory

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.

Related items

Geographical Week

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

Subscribe to Geographical!

University of Winchester

EDUCATION PARTNERS

Aberystwyth University University of Greenwich The 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 Human Game – Tackling football’s ‘slave trade’
    Few would argue with football’s position as the world’s number one sport. But as Mark Rowe discovers, this global popularity is masking a sinister...
    Essential oil?
    Palm oil is omnipresent in global consumption. But in many circles it is considered the scourge of the natural world, for the deforestation and habita...
    Mexico City: boom town
    Twenty years ago, Mexico City was considered the ultimate urban disaster. But, recent political and economic reforms have transformed it into a hub of...
    When the wind blows
    With 1,200 wind turbines due to be built in the UK this year, Mark Rowe explores the continuing controversy surrounding wind power and discusses the e...
    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...

MORE DOSSIERS

NEVER MISS A STORY - Follow Geographical on Social

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...

Deserts

An evening discussing Oman’s hidden conservation heritage. Fifty Geographical readers…

Deserts

Biosphere 2 was one of the most ambitious experiments in…

Forests

High-quality, affordable drones can revolutionise the way that landscape and…

Mapping

Benjamin Hennig charts the impact of volcanoes on nearby human…

Mapping

A volunteer-led digital mapping project is at the heart of…

Cities

As the planet urbanises, attention is turning towards the most…

Forests

Palm oil is omnipresent in global consumption. But in many…

Cities

A rising number of cruise ships and their ‘overlooked’ diesel…

Mapping

Benjamin Hennig charts the growth and impact of the world’s…

Deserts

Long-term studies reveal the Sahara desert has expanded substantially over…

Water

South America’s wealthiest economy is at a crossroads between environmental…

Forests

The European Court of Justice finds the logging of a…

Mountains

In this extract from his new book, Tides, mountain climber…

Cities

New data from the World Health Organization reveals that nine…

Water

In the wake of the water crisis in Flint, Michigan,…

Mapping

Benjamin Hennig maps out the global production and distribution levels…

Water

Millions of Americans are living in areas at high-risk of…

Mapping

New interactive maps combine precipitation and temperature to show climate…

Cities

Public transport in India could be on the verge of…

Water

To retrace the route of the fur voyageurs on the waterways…