NASA satellite images show severity of California drought
As the West descends deeper into drought, climate and water experts are growing increasingly alarmed by California's severely shriveling reservoirs.
On Monday, Shasta Lake — the largest reservoir in the state — held a scant 1.57 million acre-feet of water, according to the U.S. Bureau of Reclamation, or about 35% of its capacity.
A series of satellite images captured by NASA show just how dramatically the water level has fallen.
One image from July 2019 shows a fuller Shasta Lake surrounded by green banks. This year, that greenness has been replaced by a tan "bathtub ring" lining the lake bed, indicating the degree to which water has fallen.
A similar pattern can be seen in images of Lake Oroville, the state's second-largest reservoir — which also has experienced a precipitous drop in its reserves — and in the Sierra, which have seen a diminishing snowpack this year.
Jeffrey Mount, senior fellow at the Public Policy Institute of California's Water Policy Center, said "everybody should be concerned" by what they're seeing.
"The reservoir levels we're looking at are near-record low, with all the prospects that they will actually be record low by the end of the summer," he said. "The mountains are dried out. The sponge is completely dry."
The satellite images are stark, and their ramifications run deep, experts said — from dead lawns and fallow fields to ecological peril and worsening wildfires. Some said they probably represent a new normal for a Golden State gone brown.
Many scientists studying California's drought point to 1976-77 as a "worst-case scenario" benchmark. That drought brought Lake Oroville to its all-time record low of 646 feet above sea level.
On Monday, the lake sat just over 661 feet above sea level, or 28% of its total capacity, according to the California Department of Water Resources.
As with Lake Shasta, the satellite images of Oroville in 2019 show a lake with a lot more water than in 2021. And at eye level today, houseboats now sit on cinder blocks because there is not enough water to hold them.
The lake's water level probably will keep dwindling, said John Yarbrough, the Department of Water Resources' assistant deputy director of the State Water Project.
Yarbrough said California typically receives the majority of its annual precipitation between early December and the end of March, so the situation is unlikely to improve for several months, if not longer.
"This lack of stored water as a result of the West-wide drought has multiple cascading impacts," he said, "including dramatically less water for our farms and communities, more stress on our electricity grid and increased wildfire risk."
Already, farmers in the state have faced such dry conditions that many have begun fallowing fields, pulling out vines and trees, and leaving empty land that once flourished.
Though the '76-77 drought was record-setting, there are several key differences that make today more challenging than even that era, said Forrest Melton, program scientist at the NASA Western Water Applications Office.
In 1977, California was cooler than it is now, Melton said, and the state was home to about 15 million fewer people. Warming temperatures and a growing population have only driven up use of resources and the demand for reliable water.
"Increasingly, our dry years are also hot years," Melton said, and "the increase in population in California adds to the challenge for water resource managers, who have to respond to both drought-related reductions to water supplies and continuing growth in demand for water."
What's more, all but a handful of the last 20 years have seen below average precipitation, researchers said.
The most recent rain year, which ended in June, was the seventh driest in Los Angeles' 144 years of records, according to Golden Gate Weather Services, and the third driest on record in the Northern Sierra region.
"We're not just moving back and forth between wet years and dry years, but the number of dry years is really increasing," said Mount of the Public Policy Institute of California. "And the wet years are getting few and far between."
In fact, the snowpack in the Sierra is nearly nonexistent today, satellite images show.
Images from 2019 show the mountain range dusted in snow — even in July — while images from this year are marked primarily by varying shades of brown.
In a post about the images, NASA Earth Observatory Managing Editor Michael Carlowicz said it's cause for concern because snow that falls onto the Sierra Nevada and other ranges becomes a "natural reservoir that slowly melts each spring and summer and flows down into the river valleys," and many of the state's resource managers rely on this to fill reservoirs.