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

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...

Water

A new device, developed at ETH Zurich, could help communities…

Forests

A new initiative to save mangrove forests in the Dominican…

Deserts

The semi-autonomous Russian republic of Kalmykia sits at the forefront…

Cities

In Mogadishu, the troubled capital of Somalia, tentative moves towards…

Mountains

Researchers have predicted the birth of a new mountain range,…

Forests

Archaeological work around Lake Malawi suggests that humans manipulated the…

Water

Maida Bilal risked all to prevent contractors building a dam…

Places

Writer and photographer John Gilbey needed a cheap way of…

Water

An EU project has revealed the extent of river fragmentation…

Mapping

A new, double-sided world map projection seeks to minimise the…

Water

 Water scarcity is predicted to rise – two experts share…

Mountains

New collaborative research from the University of Oxford and the…

Places

Conceived during the late 1800s, Letchworth Garden City was the…

Places

Multiple failed attempts to build on a patch of land…

Deserts

New 'deep learning' technology is helping to identify trees in…

Places

The land around the Kinabatangan River in the state of…

Places

Highlights from the column that keeps you connected with the…

Places

At the end of a perplexing and thought-provoking year, we…

Places

The city of Mosul is slowly putting itself back together…