Recent flooding across the U.S. Southwest has provided rare relief to reservoirs that had fallen to record lows amid a yearslong megadrought.

Storms in late October and early November sent torrents of water through normally small or dry creeks that overflowed their banks and flooded local communities, forcing hundreds of people to evacuate and cutting off access to some areas.

Yet most of that water will end up feeding depleted lakes and underground aquifers, said Martin Hoerling, a climate scientist and hydrologist at the University of Colorado, Boulder, who called it "somewhat of an unexpected boost from Mother Nature."

Last winter's lackluster snowfall did little to recharge water bodies when it melted in spring and summer, the season that typically delivers their biggest bump of the year.

The chaotic climate phenomenon El Niño has intensified the heavy rain and floods that struck the region, and experts say its impacts will last several more months, potentially further boosting water supplies across the West, where water is primarily stored in lakes, aquifers and snowpack.

Cities in the region reported some of their wettest weather in decades. The storms dumped about 7 inches of rain around Pagosa Springs, Colorado, in October, lifting water restrictions that had covered more than 10,000 people in the town and surrounding communities.

Town manager David Harris, quoted in the AP report carried by PBS, called the storm destructive but saw a silver lining: "You're getting a good start to the winter snowpack in the higher elevations."

Lake Powell, the second-largest reservoir in the U.S., rose more than 20 feet (6.1 meters) from its mid-September low, dwarfing its gains from this year's snowmelt, according to Hoerling.

Still, the lake remained just over a quarter full, and 15 of its 17 boat launches remained unusable as of Friday.

Hoerling estimated the floodwaters and additional rain could raise the lake along the Arizona-Utah border by a total of over 1.2 million acre-feet — enough to support around 4 million average families for a year.

In northern Arizona, Upper Lake Mary, which supplies Flagstaff with up to 40% of its water, received more than 3 billion gallons since early October, and water production manager Brian Huntzinger told the AP that last weekend's storms dumped the equivalent of more than two years of water into the town's surface water supply.

The relief reached individual utilities, not just the big reservoirs.

In central Arizona, heavy floodwaters that trapped people in their homes gushed into streams that feed the Verde River, prompting water officials to release water from two nearly full dams into the Verde's normally dry stretch in metro Phoenix, said Bo Svoma, principal meteorologist at the Salt River Project, which manages reservoirs on the Salt and Verde rivers.

Flagstaff's Huntzinger said the new water provided a buffer for an operation that depends heavily on underground aquifers, adding, "We might be overflowing at this rate before we see any snow fly."

Pagosa Springs' restaurants had been encouraged to serve water only on request; those restrictions are now lifted, according to town manager David Harris.

Despite the intense rains, the region remains in drought, and decisions already made to divvy up water in the Colorado River basin are unlikely to change.

According to the AP report, U.S. Bureau of Reclamation spokesperson Mary Carlson acknowledged conditions have improved but added that "considerable uncertainty remains."

Utah State University professor Jack Schmidt, who studies the Colorado River, said the agency is unlikely to change its water releases from Lake Powell or other areas until it knows when snowpack has peaked, typically around April.

Under the federal plan for the Lower Basin, California, Nevada and Arizona will collectively reduce water use by 1.25 million acre-feet annually over the next two years — enough to fill over 600,000 Olympic-sized swimming pools — with Nevada and Arizona challenging the plan in court.

"We need to figure out how to be resilient in a drier future. And we're not quite there yet," Hoerling said.