Lake Powell Rose 20 Feet. It’s Still Barely a Quarter Full.

In late October, floodwater forced people out of their homes in southwestern Colorado. Farther downstream, some of that same water brought a welcome surprise: Lake Powell, the nation’s second-largest reservoir, climbed more than 20 feet from its September low. After a winter that delivered little relief, a few weeks of storms gave the lake a bigger boost than the spring snowmelt did.

Then comes the number that puts the whole thing in perspective. As of Saturday, Lake Powell was about 27 percent full. Even after gaining 20 feet, its surface was still roughly 161 feet below full and more than six feet lower than it was a year earlier.

Upstream, the rain was anything but good news. In Pagosa Springs, Colorado, the San Juan River flooded twice in less than two weeks. Officials ordered people out of downtown and closed bridges. The town manager estimated the first flood alone caused $38 million in damage within town limits. The same river that tore up roads and riverbanks was carrying water toward a reservoir that badly needed it.

For the people who manage the Colorado River, every extra foot at Lake Powell matters. Glen Canyon Dam generates electricity by sending water through turbines. If the lake falls below 3,490 feet above sea level, the water can no longer reach those turbines. Saturday’s reading put the lake about 49 feet above that line. That’s breathing room, and a good reason to pay attention to what happens this winter.

The storms haven’t settled the fight over who gets how much of the Colorado River. Under a federal plan, Arizona, California and Nevada would collectively cut their water use by 1.25 million acre-feet a year over the next two years. Arizona and Nevada are challenging the plan in court. And federal water managers are unlikely to change releases from Lake Powell before they have a clearer picture of the mountain snowpack, which typically peaks around April.

The Southwest got a reprieve from an unlikely source: storms fierce enough to drive people from their homes. Now the region needs something less dramatic and more dependable—a winter that leaves enough snow in the mountains to keep the river running when the rain stops.