Lake Powell sank to a record 3,517 feet, nearing the level that stops Glen Canyon Dam’s turbines

On September 10, 2026, the surface of Lake Powell stood at 3,517.24 feet above sea level, the lowest level on record and 2.68 feet under the previous record of 3,519.92 feet set on April 13, 2023. The gap that matters now is the one below: 3,490 feet, the minimum power pool, under which the dam’s hydroelectric turbines can no longer generate power effectively.

That leaves about 27 feet of water between the second-largest reservoir in the United States and a mechanical limit built into a 1960s dam, at the end of a year in which the mountains that feed it produced very little snow.

A record that was set twice in a month

NASA’s Earth Observatory, in a September 18 image story by Lindsey Dauphin, says the lake first fell to a record on August 15 and kept declining into early September. Landsat 8 imagery from September 10 shows the lake as a narrow, winding channel through desert canyon country, next to a frame from September 2017 in which the same canyons are brimming. Reclamation’s own Glen Canyon Dam page gave 3,517.87 feet on August 31 and a storage of 5.14 million acre-feet, 22 percent of live capacity, with the full pool roughly 183 feet higher.

The cause is upstream. NASA attributes the drop to unusually little snow in the Upper Colorado Basin over winter 2025-2026 and stretches of record warmth that trimmed what snow there was, so spring melt delivered a fraction of the water the lake normally receives. The drought behind it is not new: NASA describes the lake’s decline as part of a Southwestern megadrought that has run since about 2000, and the 2023 record that fell this summer was itself set in the wake of that dry stretch.

What crossing 3,490 feet would actually do

Glen Canyon Dam drives its generators through eight 15-foot penstocks that Circle of Blue says become useless below the minimum power pool. The reporting in Circle of Blue describes the fallback as four much smaller river outlet works, never designed for continuous duty, which Reclamation estimates can pass water until roughly 3,394 feet and which a March 2024 agency technical memo warned would accelerate maintenance if used long term. Below 3,370 feet, the reservoir’s dead pool, no water leaves the dam at all.

The stakes are bigger than one power plant. NASA notes the Colorado River supplies water and electricity to more than 40 million people, including in Las Vegas, Phoenix, Los Angeles and San Diego, and water to some 5 million acres of Southwestern farmland. Reclamation says the dam is currently holding 30 megawatts of generation capacity in reserve for power-system emergencies.

Where the water came from to slow the fall

Federal managers did not wait for the record. In April, Interior Assistant Secretary for Water and Science Andrea Travnicek said action was needed quickly “to protect a resource that supplies water to 40 million people,” according to Colorado Sun coverage of the plan to trim Glen Canyon Dam releases to 6 million acre-feet from 7.48 million. Reclamation’s August 24-Month Study confirms that cut for water year 2026 and says between 660,000 and one million acre-feet is being moved down from upstream reservoirs through April 2027.

The upstream source is Flaming Gorge, which Reclamation’s Flaming Gorge status page lists at 6,009.95 feet on September 1, at 70 percent of live storage, having started the drought operations about 82 percent full. It also lists August inflow at only about 63 percent of the historical average, so the donor reservoir is drying as well.

NASA’s account says Reclamation began the Flaming Gorge releases and lowered the downstream flows in April specifically to hold Powell above 3,490 feet. It also says the agency canceled a planned spring high-flow experiment and an August cool-mix release, according to a ScienceDaily digest of the NASA piece, giving up management tools to save the extra elevation. The digest adds that Lake Mead, the reservoir downstream that receives Powell’s releases, also hit record lows in August.

The margin the numbers leave

Reclamation’s August projection, the most probable case, has the lake ending water year 2026 at 3,515.89 feet, about 26 feet above the power pool, with 5.03 million acre-feet in storage. The same study says elevation is expected to drop below 3,510 feet during water year 2027 and moves operations into what the agency calls the Low Elevation Infrastructure Protection Range.

Whether that is enough depends on a winter that has not happened yet. Circle of Blue reports that Reclamation expects an appraisal of three dam-modification options by the end of 2026 or early 2027, and that any of them would need congressional authorization before construction could start.

This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.

More from Morning Overview