Earth

Drought still grips southern California

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Eleanor Imster

and

Deborah Byrd

and

November 19, 2016

Acquired November 8, 2016. image via NASA — Drought conditions in southern California as of November 8, 2016. Exceptional drought shown in maroon, and extreme drought in red. Image via U.S. Drought Monitor and NASA Earth Observatory.

While late summer and autumn rains offered some relief to northern California, drought continues in the southern part of the state, said NASA’s Earth Observatory this week. Exceptional drought can bring widespread crop and pasture losses, as well as water emergencies due to low reservoirs, streams, and wells. Meanwhile, the U.S. Forest service said on November 18, 2016 that its latest aerial survey reveals more than 100 million trees dead in California.

The map at the top of this page depicts southern California’s ongoing drought according to the classification system of the U.S. Drought Monitor. NASA Earth Observatory said:

The map is based on measurements of soil, water, and climate conditions collected by federal, state, and local observers. NASA also provides experimental measurements and models to the drought monitoring effort.

Remarkably low water levels in many reservoirs in Southern California are another indicator of the severity of the drought. For instance, the volume of water in Lake Cachuma—which supplies Santa Barbara with drinking water—has fallen to about 7 percent of capacity. The Operational Land Imager (OLI) captured images (below) of the reservoir on October 27, 2013, and October 26, 2016. The sharp decline in water levels has exposed much of the bottom of the reservoir. Image via NASA Earth Observatory. — Very low water levels in many reservoirs in Southern California are an indicator of the drought’s severity. This comparison shows Lake Cachuma, which supplies Santa Barbara with drinking water. It has fallen to about 7 percent of capacity. Images acquired by satellite October 27, 2013, and October 26, 2016, via NASA Earth Observatory.

While the extent and severity of drought has fluctuated over the months and years, the large zone of exceptional drought in southern California has persisted since January 2014. The chart below shows how extreme the current drought has been in comparison to past dry spells. NASA said:

While the state has experienced several dry periods since 2000, none pushed any portion of the state into exceptional drought. About 20 percent of California remains in exceptional drought now.

Read more from NASA’s Earth Observatory

Based on data acquired via satellite January 4, 2000 - November 8, 2016. Graph via NASA Earth Observatory. — Based on data acquired via satellite January 4, 2000 – November 8, 2016. Graph via NASA Earth Observatory.

Here’s more about the November 18 report from the U.S. Forest Service that California now has more than 100 million dead trees:

The U.S. Department of Agriculture (USDA) announced today that the U.S. Forest Service has identified an additional 36 million dead trees across California since its last aerial survey in May 2016. This brings the total number of dead trees since 2010 to over 102 million on 7.7 million acres of California’s drought stricken forests. In 2016 alone, 62 million trees have died, representing more than a 100 percent increase in dead trees across the state from 2015. Millions of additional trees are weakened and expected to die in the coming months and years.

This massive die-off of tree in California forests increases the risk of catastrophic wildfires and other threats to humans.

New Aerial Survey Identifies More Than 100 Million Dead Trees in California: https://t.co/J0WPeRD1rl

— U.S. Forest Service (@forestservice) November 18, 2016

Dead trees in Kings Canyon National Park in California, via the Sierra Nevada Conservancy and KCBX.

Bottom line: While dry spells are not uncommon in southern California, none since 2000 has pushed any portion of the state into exceptional drought. About 20 percent of California remains in exceptional drought now.

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November 19, 2016

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Earth

Eleanor Imster

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About the Author:

Eleanor Imster has helped write and edit EarthSky since 1995. She was an integral part of the award-winning EarthSky radio series almost since it began until it ended in 2013. She and her husband live in Tennessee, where they enjoy guitar playing and singing. They have 2 grown sons.

Deborah Byrd

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About the Author:

Deborah Byrd created the EarthSky radio series in 1991 and founded EarthSky.org in 1994. Prior to that, she had worked for the University of Texas McDonald Observatory since 1976, and created and produced their Star Date radio series. Today, she serves as Editor-in-Chief of this website. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named 3505 Byrd in her honor. In 2020, she won the Education Prize from the American Astronomical Society, the largest organization of professional astronomers in North America. A science communicator and educator since 1976, Byrd believes in science as a force for good in the world and a vital tool for the 21st century. "Being an EarthSky editor is like hosting a big global party for cool nature-lovers," she says.