Lake Powell forecast 13% runoff

Lake Powell is the giant savings account in the middle of the Colorado River system. When inflow into Powell collapses, the problem is not just one reservoir looking ugly on a map. It ripples into hydropower, downstream deliveries, and the whole political fight over who cuts water use next. That is why this week’s forecast landed so hard: federal forecasters now think Powell will get only 13% of its normal spring runoff in 2026, the worst such inflow since the reservoir filled in the 1960s. ### What actually changed? The big change was the forecast itself. The Colorado Basin River Forecast Center’s May 1 update put April-through-July unregulated inflow to Lake Powell at 800,000 acre-feet, down to 13% of average. Just a couple months ago, the outlook was bad but not this bad. By early May, the remaining uncertainty had mostly broken in the wrong direction. ### Why did the forecast fall apart? (cbrfc.noaa.gov) Because the basin got hit by the worst combination for runoff — weak snowpack, dry soils, and heat at the wrong time. A lot of the Upper Colorado started the season behind on snow, then March warmth sped up melt and evaporation. So even where snow did fall, less of it turned into river water reaching Powell. Basically, the mountains did not build the spring reservoir the river depends on. ### Why is 13% such a big deal? Because Powell is not just a lake. It is the buffer that helps the Upper Basin meet downstream obligations and keeps Glen Canyon Dam functioning normally. Thirteen percent of average means the reservoir gets almost none of the seasonal refill it usually counts on. At 800,000 acre-feet, this is not a normal dry year — it is a system-stress year. (kunc.org) ### What is “minimum power pool”? That is the elevation where Glen Canyon Dam can no longer generate hydropower through its turbines. Reclamation says that threshold is 3,490 feet, and its February 24-month study projected Powell could reach it in December 2026 under the most probable scenario. Drop lower and the dam still matters for releases, but one of its core jobs — making electricity — starts to fail. (lasvegassun.com) ### Does this mean the lights go out this summer? Not automatically. The immediate risk is not that homes across the Southwest suddenly lose power tomorrow. The risk is that a bad runoff season pushes Powell low enough that hydropower becomes unreliable or stops later this year if conditions do not improve and managers cannot hold enough water back. Reclamation has already been adjusting releases to retain more water in Powell. (usbr.gov) ### Why are the Lower Basin states moving now? Because the reservoirs were already too low before this forecast got worse. Arizona, California, and Nevada announced a temporary plan to conserve up to 1 million additional acre-feet through 2028, on top of earlier reductions, bringing the proposed total to 3.2 million acre-feet with Mexico included in the broader framework. The point is to buy time before new long-term operating rules kick in. (usbr.gov) ### So what is really at stake? Water deliveries, power revenue, and negotiating leverage. Hydropower from Glen Canyon helps fund river operations and environmental programs. If Powell keeps sliding, the basin loses flexibility at the exact moment states are trying to hammer out the post-2026 rules for sharing a shrinking river. That makes every forecast revision feel political as well as hydrologic. (bostonherald.com) ### Bottom line The scary part is not just the 13% number. It is what that number says about the Colorado River’s margin for error — basically, there isn’t much left. One failed snow season now pushes straight into power risk, emergency operations, and another round of water-cut bargaining across the Southwest. (coloradosun.com)