Lake Powell rises 20 feet as floods bring rare relief to Southwest

Lake Powell has risen more than 20 feet since mid-September as late-October storms flooded the U.S. Southwest, offering rare relief to a reservoir that fell to a record low this summer.

The storms killed at least one person, trapped residents in their homes, and left communities from Colorado to New Mexico buried in mud, as the Associated Press reported. More than 20 trillion gallons of rain fell on the Four Corners states and Nevada in two weeks, according to calculations by Ryan Maue, a former chief scientist at the National Oceanic and Atmospheric Administration.

Most of that water will end up in depleted lakes and underground aquifers, said Martin Hoerling, a climate scientist and hydrologist at the University of Colorado, Boulder. The gain is real, but the reservoir remains just over a quarter full, and the federal government is unlikely to change water-sharing cuts before spring snowpack peaks in April.

Lake Powell is the second-largest reservoir in the United States, straddling the Arizona-Utah border. It fell to a record low in August, as the Los Angeles Times reported, part of a crisis on the Colorado River that also drove Lake Mead to its lowest level ever recorded the same month, the Times separately reported.

The 20-foot rise dwarfs what the reservoir gained from this year’s snowmelt, Hoerling said. Floodwaters and further rain could raise Lake Powell by a total of more than 1.2 million acre-feet, enough to supply about 4 million average families for a year, he estimated.

Even so, 15 of the lake’s 17 boat launches remained unusable as of Nov. 7, according to the AP.

Last winter’s snowfall was lackluster and did little to recharge the region’s water bodies when it melted. Then El Niño intensified, and the climate pattern is expected to keep delivering heavy rain across the West for several more months.

In Pagosa Springs, Colorado, about 7 inches of rain fell in October. Before the storms, more than 10,000 people in the town and surrounding communities were under water restrictions. Those restrictions are now lifted, said town manager David Harris.

“While the storm was destructive, I think there is a silver lining,” Harris said. “You’re getting a good start to the winter snowpack in the higher elevations.”

Upper Lake Mary, which captures spring snowmelt in northern Arizona and supplies Flagstaff with up to 40% of its water, received more than 3 billion gallons since early October, said Brian Huntzinger, Flagstaff’s water production manager. Storms last weekend dumped the equivalent of more than two years of water into the town’s surface water supply.

“It’s just a great, great thing to see,” Huntzinger said. “We might be overflowing at this rate before we see any snow fly.”

In central Arizona, floodwaters that trapped people in their homes gushed into streams that feed the Verde River. Water officials released water from two nearly full dams into the river’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.

The region remains in drought despite the rain. The U.S. Bureau of Reclamation, which manages reservoirs in the West, is unlikely to change its water releases from Lake Powell or other facilities until it knows when snowpack has peaked, typically around April, said Jack Schmidt, a Utah State University professor who studies the Colorado River. Reservoir data published by the bureau is updated daily, according to its HydroData portal.

Reclamation spokesperson Mary Carlson said conditions have improved but “considerable uncertainty remains.”

Under the federal plan for managing the Colorado River’s Lower Basin, California, Nevada and Arizona will collectively reduce water use by 1.25 million acre-feet annually over the next two years. That is enough to fill more than 600,000 Olympic-sized swimming pools, with the possibility of larger cuts depending on conditions. Nevada and Arizona are challenging the plan in court.

Some Arizona cities have agreed to fund preliminary work to expand an existing dam on the Verde River to capture storm runoff, reducing reliance on the Colorado River, Svoma said.

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

What I think

The 20-foot number will lead the coverage, and it should, because it is the largest single gain Lake Powell has seen in years. But a reservoir that is still three-quarters empty after rising 20 feet has not recovered. It was so low that a 20-foot jump leaves it at a quarter of capacity, with 15 of 17 boat ramps closed. The number that matters more is the one the Bureau of Reclamation is watching: how much snow falls in the Rockies this winter, and how much of it reaches the river in April.

The flooding that produced this gain killed at least one person and destroyed homes in Colorado and New Mexico. The same storms that replenished Upper Lake Mary turned Willow Bradner’s basement in Durango into what she called a soup bowl, with nearly five feet of water pouring through an overflowing creek. Reading the reservoir story and the flood story together is the only honest way to read either one. The water did not arrive gently.

The Bureau of Reclamation is right to wait. A wet October does not predict a snowy winter, and the Colorado River’s allocations are set by April snowpack, not by autumn floods. The 1.25 million acre-feet in cuts that California, Nevada and Arizona are absorbing for the next two years were negotiated because the reservoirs spent years falling. One wet month does not reverse that, and Carlson’s phrase, “considerable uncertainty remains,” is the accurate read.

El Niño may keep delivering rain through the winter. That is the best case, and even in the best case the lake starts from a record low set in August. The Southwest’s water problem is structural. The river is overallocated, the region is hotter and drier than it was when the compact was signed a century ago, and 40 million people depend on a system designed for a climate that no longer exists. A flood year buys time. It does not buy a solution, and anyone who reads the 20-foot headline as a sign the crisis has eased is reading the number without the denominator.

The towns that lifted water restrictions and the reservoirs that rose are the immediate winners. The people digging mud out of their living rooms are the immediate losers, and they live in the same watersheds. Hoerling’s last line is the one that holds: the region is not yet resilient in a drier future. A 20-foot rise in Lake Powell is a reprieve, not a fix, and treating it as anything more is how the next shortage catches people off guard.