How Lake Mead's Water Levels Changed During Hilary

Lake Mead's water levels have risen slightly after storm Hilary battered northern Mexico and California in recent days.

Before the storm hit the region, the lake's water levels stood at 1,063.49 feet. On August 20, they rose to 1,063.62 feet and on August 21, the second day of the storm, water levels stood at 1,063.78 feet. On August 22, the levels rose to 1,064 feet.

Before the storm made landfall in California, forecasters warned that it could cause flash floods around Lake Mead—which is the largest manmade reservoir in the U.S. and lies between Nevada and Arizona, near the California border.

While the increases in water levels during Hilary are not huge, any rise in the drought-stricken reservoir is worth noting.

This is because the reservoir has been severely affected by drought over the past few years, meaning its water levels have been incredibly low. Last summer, it reached 1,040 feet, which is the lowest it has been since it was first constructed in the 1930s.

Lake Mead has been refilling this year due to a particularly wet winter and early spring period. A record amount of snowpack accumulated in the surrounding mountains which then melted, replenishing the Colorado River basin.

At the beginning of 2023, the lake's water levels stood at 1,044 feet following a bone-dry summer. But since spring, the water levels have increased sharply.

Over the winter, the area saw intense rain and snow storms that built up snowpack. As this melted in the springtime, Lake Mead's water levels rose from 1,047 feet on April 25, to 1,054 feet at the end of May.

It remains to be seen how much of this rise was caused by Hilary, and how much was caused by the melting snowpack.

Although the wet periods seen this year have provided much needed replenishment for the reservoirs, experts have warned that it is not likely to lift the Southwest out of the water crisis in the long term.

"It is really natural to see the storms associated with Hilary and to imagine these rains are helping to solve our drought problem in the Colorado River basin. If only it were that easy," Andrea K. Gerlak recently told Newsweek.

Gerlak is a director of the Udall Center for Studies in Public Policy and a professor in the School of Geography, Development & Environment at the University of Arizona.

"Rain falling over our reservoirs can certainly help with lake levels and water supplies, but it is small in the grand scheme of things," Gerlak said.

"What Hilary reveals for me is that storms and weather patterns can provide an opportunity for the public to better understand where our water supplies come from and the causes associated with drought and shortage in the larger basin. This is a necessary first step to finding sustainable, long-term solutions."

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