In Parched Southwest, Warm Spring Renews Threat of ‘Megadrought’

DNYUZ – July 8, 2020

LOVELAND PASS, Colo. — Here at 12,000 feet on the Continental Divide, only vestiges of the winter snowpack remain, scattered white patches that have yet to melt and feed the upper Colorado River, 50 miles away.

That’s normal for mid-June in the Rockies. What’s unusual this year is the speed at which the snow went. And with it went hopes for a drought-free year in the Southwest.

“We had a really warm spring,” said Graham Sexstone, a hydrologist with the United States Geological Survey. “Everything this year has melted really fast.”

The Southwest has been mired in drought for most of the past two decades. The heat and dryness, made worse by climate change, have been so persistent that some researchers say the region is now caught up in a megadrought, like those that scientists who study past climate say occurred here occasionally over the past 1,200 years and lasted 40 years or longer.

Even a single season of drought is bad news for the Southwest, where agriculture, industry and millions of people rely on the region’s two major rivers, the Colorado and the Rio Grande, and their tributaries for much of their water. Dry conditions also shrivel crops, harm livestock and worsen wildfires.

But droughts, even long ones, eventually end, when the natural variability of climate results in a few “good,” meaning wet, years in a row. So after a relatively cool and wet spring last year followed by a decent snowpack in the fall and winter, there was some optimism that 2020 might be remembered as the year the long Southwestern drought started to fade.

But then came April and May, which were warm and dry, leading to rapid melting and runoff.

Normally, Dr. Sexstone said, measurements of stream flow at gauges in the region would slowly climb to a peak and then drop off gradually as the season progressed.

“This year it seemed like it peaked and then plummeted,” he said.

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