Lake Mead, the largest reservoir in the US, has dropped to its lowest water level in history, sparking urgent warnings that water shortages and power outages could be coming soon.
Formed by the Hoover Dam on the Colorado River between Nevada and Arizona, the reservoir was once considered full when the water level was at a height of 1,220 feet above sea level. As of Tuesday, the water had dropped just under 1,040 feet.
The massive drop-off, and a similar decline at the Glen Canyon Dam, which supports another reservoir fed by the Colorado River 300 miles away, may soon lead to hydroelectric power production being shut off at both facilities.
The US Bureau of Reclamation, which manages dams and reservoirs, has warned that each dam is just feet away from being forced to shut down their turbines, which supply nearly two million people with electricity in Arizona, California, Colorado, New Mexico, Nevada, Nebraska, Wyoming and Utah.
Overall, 30 to 40 million people could be affected by the Colorado River drying up, as seven states rely on the major waterway for drinking water, household plumbing and farming.
Cities such as Las Vegas, Phoenix and Los Angeles, as well as many smaller towns across the Southwest, get a large share of their water from these reservoirs.
The water crisis stems from extreme drought conditions throughout the region, but particularly near the Colorado River’s source in the Rocky Mountains, where very low snowpack totals have meant less frozen water melting into the river to fill it.
The problem has become so dire that the dropping water levels in Lake Mead and Glen Canyon Dam’s Lake Powell can be seen from passenger planes thousands of feet high flying into the Southwest.
Pictured: Hoover Dam, which holds back the largest reservoir in the US, Lake Mead
The former water line in Lake Mead can be visibly seen from passenger planes flying over Arizona and Nevada
At Lake Mead, the power outage problem has already reached alarming levels. Lake Mead’s current water levels sit just five feet from hitting the point where older turbines at the hydroelectric facility will be forced to shut down to avoid damage.
Only newer ‘wide-head’ turbines can keep running at the lower water levels, however, this will lead to a sharp drop in power output.
The power coming out of Lake Mead at Hoover Dam serves over one million people across Arizona, California and Nevada. It generates about four billion kilowatt-hours of hydroelectric power each year.
Once the drought conditions drop those levels below 950 feet, the entire facility will have to shut down.
Lake Powell is just 30 feet away from dropping to the point where its hydroelectric turbines will need to shut down, adding another 300,000 people across the Great Plains and Southwest to the power crisis.
If the water in Lake Powell or Lake Mead drops too low for the dams to generate power, utilities that normally buy the cheap hydropower will have to scramble for replacement power from other sources.
Typically, this means more expensive natural gas or other options which can raise electricity bills for customers in the region and put further strain on the power grid – increasing the risk of a blackout in extreme conditions.
The water itself can still be released downstream through smaller pipes, but with less control and capacity, making it harder to manage supplies for cities to use in homes and farms to use for crops.
Lake Mead and Hoover Dam near capacity in 1983 (Left) compared to conditions in 2026 (Right)
US Bureau of Reclamation projections, released on July 15, show the iconic Lake Mead’s levels could likely drop by 33 feet over the next two years
JB Hamby, chairman of the Colorado River Board of California told the Associated Press: ‘It’s extremely significant and extremely concerning. You have three-quarters of the population of the Colorado River Basin, some 30 million people, who are directly impacted by risks to Lake Mead.’
A July report by the Bureau of Reclamation projected that the Lake Mead reservoir could drop by another 33 feet in the next two years. The reservoir is currently operating at less than 27 percent capacity.
One local, named John Belton, wrote online: ‘There’s only two things that can save Mead and Powell right now: 150 percent Colorado Rockies snow pack for five consecutive years, or God himself.’
Unfortunately, conditions are only predicted to worsen, especially this week, as a massive heat dome moves over the western half of the US.
AccuWeather has forecasted that high heat and humidity will combine to make states from Arkansas to California have a ‘feels like’ temperature near or surpassing 100 degrees Fahrenheit.
Higher temperatures increase evaporation and reduce runoff, meaning even less snowpack from the Rockies will make it to the Colorado River and replenish the region’s water supply.
Last month, the Bureau of Reclamation released a ten-year plan for how to operate Lake Powell and Lake Mead after the current rules expire at the end of 2026.
With the two lakes falling to record lows, the plan allows for mandatory water cuts, referred to as ‘shortages,’ across Arizona, California and Nevada.
The cuts were estimated to be up to 40 percent of what those states currently get from the reservoirs.
Hamby said: ‘The proposal responds to a fundamental reality: the Colorado River no longer reliably produces enough water to support all the uses and expectations built around it.’
