The Colorado River Crisis: Can a Record-Strong El Niño Reverse Decades of Damage?
Stretching across seven U.S. states and supplying water to 40 million people, the Colorado River has reached a catastrophic tipping point. The nation’s two largest reservoirs, Lake Mead and Lake Powell— which act as the core water storage hub for lower river basin states— both dropped to all-time record lows just this month.
Now, a major weather event is poised to enter the picture: an El Niño that is on track to become the strongest ever recorded. Forecasts predict this climate pattern will bring above-average rain and snowfall to the American Southwest this winter and spring. But water and climate experts warn that even this extra precipitation will almost certainly not be enough to reverse the slow-building disaster unfolding along the river. Even the most optimistic outcome— a winter that builds a robust, healthy snowpack to temporarily top up river levels— cannot overcome the deep, long-term problems pushing the Colorado to the brink.
The Colorado River’s water supply is primarily fed by snowmelt from mountain ranges in the four Upper Basin states: Colorado, Utah, New Mexico, and Wyoming. That runoff then flows downstream to serve three Lower Basin states: California, Arizona, and Nevada, with Lakes Powell and Mead acting as critical storage for these communities.
Last winter, the entire Western U.S. saw record-breaking warm temperatures (a trend made far more likely by human-caused climate change) paired with some of the lowest mountain snowpack levels on record across multiple states. The result is an unprecedented dry spell for the Colorado. As of a recent Thursday measurement, Lake Powell sat at 3,519.4 feet above sea level, while Lake Mead measured 1,039.6 feet— both new historic lows.
If levels continue to drop, each reservoir will eventually reach a threshold called “deadpool”: 3,370 feet for Lake Powell and 895 feet for Lake Mead. At deadpool, water can no longer flow downstream out of the reservoirs. Critically, hydropower generated by the dams at both reservoirs will be disrupted or shut down completely long before this threshold is hit.
Compounding the physical water shortage is a uniquely timed political crisis. For decades, the Colorado River’s water has been overallocated, with more water promised to water-intensive industries like agriculture than the river can actually sustain. To make matters worse, the century-old legal compact that governs water rights along the river expires at the end of this year. So far, states have missed multiple deadlines to negotiate a new agreement for dividing the river’s dwindling supply, forcing the federal government to step in.
Combined with plummeting reservoir levels, this gridlock has turned a decades-long slow-burning crisis into an urgent emergency, researchers say. “People have talked about the Colorado River crisis for decades—we’re now in it,” says John Berggren, policy manager at environmental nonprofit Western Resource Advocates. “Everyone you talk to is like, ‘Shit, man. This is the year. Next year is the year.’ We’re really going to see: Can we get through it?”
A wet, snowy winter this year could buy state and federal officials much-needed breathing room as they rush to lock in a long-term plan for the river’s future. It is true that El Niño will likely bring some relief to parts of the region dependent on the Colorado’s water. Zeke Hausfather, a climate scientist at Berkeley Earth, notes that one of the most reliable El Niño impacts is increased wet weather across southern parts of the U.S., including multiple states that draw water from the Colorado. “A strong El Niño does load the dice toward a wet winter across the southern US, from Southern California through Arizona and New Mexico to the Gulf Coast,” he explains.
The big open question, however, is whether the critical Upper Basin states— whose snowmelt actually replenishes Lakes Powell and Mead— will get enough snowfall to move the needle. During the last very strong El Niño in winter 2015-2016, the Upper Basin only saw average snowfall. “Peer-reviewed correlations between El Niño and Upper Basin snowpack or streamflow are modest at best,” Hausfather says.
This year’s El Niño is shaping up to be stronger than any previously recorded. Daniel Swain, a climate scientist with University of California Agriculture and Natural Resources, points out that a typical El Niño and a “ridiculously strong El Niño” are “almost two completely distinct things.” Given how intense this event is projected to be, there is a small chance the Upper Basin could see above-average precipitation. Even so, all experts agree the Lower Basin will be the region most impacted by increased rain and snow— which does little to refill the two major reservoirs or boost the river’s overall long-term supply.
Climate change has also shifted the baseline for Western winters, making warm winters and snow drought far more common than they were a generation ago. While Swain does not expect this winter to be as warm as last year’s record-setting warm winter, rising temperatures have fundamentally changed how even extra precipitation contributes to river flow. Extra precipitation can be “intercepted by drying soil, or re-evaporated directly into a thirstier atmosphere, or [fall] as rain rather than snow,” Swain says. “That won't have the same effect as a good snow year in 1980 or 1990.”
All experts agree that even the best-case scenario— a record-breaking snowpack year in the Colorado’s source mountains that pulls both reservoirs back from the deadpool brink— would still not be enough to meaningfully fix the river’s crisis. El Niño is also expected to temporarily push global temperatures even higher next year, highlighting how rapidly climate change is transforming the planet. Some projections estimate the Colorado River’s total flow could shrink by as much as 30% by 2050 due to ongoing warming.
“Even one big year is not going to save us,” Berggren says. “It might be a sigh of relief, but we'll be right back in it.”
