The state of California has experienced a significant increase in its two largest reservoirs following a series of atmospheric river storms that hit the region in December and January. Before-and-after satellite photos from NASA Earth Observatory showed the stark difference between the two images, indicating the impact of the early-winter storms. Lake Shasta, California’s largest reservoir, was at just 31% of capacity on November 19th. However, on January 29th, it had risen to 56%, according to the California Department of Water Resources. The latest data shows the reservoir has climbed further to 60%, which is still below historical levels for February but significantly higher than it had been.
Lake Oroville, another critical component of California’s water supply, also benefited from the early-winter storms, as satellite images showed that it had increased from 28% to 64% by January 30th, before hitting 72% on Monday, which is well above its historical average for February, 63%. Despite the significant improvement in reservoir levels, California still faces a severe drought. Water experts have noted that it will take more than a series of storms to make up for the years of water deficits.

Groundwater levels have been depleted, and some areas such as the Central Valley still have dangerously low levels. Stormwater capture has failed to live up to promises in Los Angeles. Additionally, the Colorado River, a significant source of water for Southern California, is also in crisis. Although the storms made a difference, it will require more comprehensive and long-term solutions to address California’s water shortage.
The complexity of water systems requires further analysis, but the Department of Water Resources spokesperson Margaret Mohr stated that the update from the U.S. Drought Monitor on Thursday showed that the state was entirely out of exceptional and extreme drought, which is an improvement. Three months prior, 41% of the state was under these classifications, and the proportion of the state in severe drought or worse had decreased from 85% to 33% in three months.