Lakes at historically low levels, unusually early wildfires, water use restrictions and now a potentially record-breaking heat wave: Even before summer begins, the western United States is suffering effects of chronic drought exacerbated by climate change.
Eighty-eight percent of the West was in a state of drought this week, including all of the states of California, Oregon, Utah and Nevada, according to official data.
A particularly glaring symptom of this trend, which affects more than 143 million Americans, Lake Mead – the country’s largest reservoir, located on the border of Nevada and Arizona – is now at its lowest level since its creation in the 1930s.
The lake, formed when the massive Hoover Dam was built on the Colorado River near Las Vegas, is only 36% of its capacity, even below the record set in 2016.
The authorities expected something like this – but not until August.
The situation in northern California, which normally receives heavy precipitation in winter and spring, is no better. Lake Oroville, the state’s second-largest reservoir and a key part of a network providing drinking water to 27 million Californians, is 50 meters (165 feet) lower than in 2019.
Widespread restrictions on water use appear inevitable over the next few months, with potentially serious ramifications for Western states, especially for irrigation-dependent farmers – who provide much of the fruits and vegetables in the world. country.
In California, whose vast almond groves provide 80% of the world’s production, some farmers have already started pulling trees to save water.
As of April 1, the date traditionally marking the region’s last snowfall, the snowpack on the upper slopes of the Sierra Nevada – the source of about a third of all water used in California – was only 60 % of the mean.
“Really, one thing that is unique this year is that when the snow melted, the runoff eventually seeped into the dry soils and evaporated,” John Yarbrough, an official for the snowmelt, told AFP. California Department of Water Resources news agency.
“So that’s what was unusual this year, how little runoff we got from that snowpack.”
According to the US Drought Monitor, a third of California is currently experiencing “exceptional drought”, the worst level.
And dry soils and water-deprived vegetation create the conditions for even higher temperatures, fueling a devastating vicious cycle.
Meteorologists have issued heat warnings, saying Las Vegas, for example, could reach 115 degrees Fahrenheit (46 degrees Celsius), breaking a record set in 1940.
Authorities are particularly concerned about the forest fires, which have happened exceptionally early this year and with rare intensity. By the end of May, the fires in California had already destroyed five times more vegetation than last year at this stage.