Weather expert reports surprising change in crucial West Coast reservoir after Hurricane Hilary: ‘This buys [us] a year’

Severe storms aren’t generally hailed as good news in weather stories.

However, in the case of Hurricane Hilary, its storm-driven rainfall helped with the ongoing drought for the Southwest’s Lake Mead — if only a bit and not without doing damage elsewhere.

The hurricane, which weakened to Tropical Storm Hilary before it made landfall in Mexico on Aug. 20, helped raise the level of Lake Mead to its highest point this year, USA Today reported.

On the Colorado River, upstream of Hoover Dam, Lake Mead is the nation’s largest reservoir by volume and spans the Nevada-Arizona border less than 25 miles east of Las Vegas.

Any rise in the reservoir is welcome news for a Southwest region with about 40 million people who depend on the river and have seen its water level decline over decades, as the Guardian reported.

USA Today noted that following Hilary’s input, Lake Mead was more than 20 feet higher than it was at the same time in 2022, though much of the increase was due to wet weather and snow this past winter.

The Weather Channel reported that Lake Mead rose about 7 inches as Hilary passed, much of this aided by less demand for water downstream, allowing less release at the dam. The channel’s report also noted that melting snow had raised the lake far more.

Although the extra rainfall on Lake Mead was helpful, the storm also left destruction.

According to the Associated Press, California saw floods, downed trees, and a dramatic rescue of older residents near Palm Springs. It caused at least one death in Mexico. Record desert rainfall also damaged Death Valley National Park so much that officials expected it to close for months.

The story of Hilary isn’t simple and illustrates the complexities of extreme weather on an overheating planet — where we’ve seen floods, drought, extreme heat, storms, and wildfires within months.

The AP noted after Hilary passed that it was “just the latest major weather event to wreak havoc across the U.S., Canada, and Mexico” and put it in the context of deadly fires that had just burned on Maui and others burning in Canada.

At Lake Mead, experts concluded that Hilary’s rains and last year’s snows have been beneficial but not enough.

“This buys a year,” Brad Udall, a Lake Mead authority, told USA Today, referring to winter snowpack and recent precipitation. “It doesn’t remotely come close to solving the long-term problems.”

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