An extraordinary, persistent storm that has been funneling moisture through New Mexico all week has led to record and near-record flows on many of the state’s rivers. But the answer to the question on everyone’s mind – “Is the drought over?” – depends on where you sit.
On the Pecos, the answer appears to be “yes,”said Greg Lewis, Pecos River Basin manager for the New Mexico Interstate Stream Commission. “I’d say it’s a drought-ender for this year,” Lewis said in a phone interview as he was surveying reservoir levels on the eastern New Mexico river.
With flows on the Pecos in some places reaching levels the river had not had since the 1940s, the storm should put enough water into reservoirs to ensure irrigation water for farmers next spring, Lewis said. That comes as good news to farmers in Carlsbad, who depend on the river’s water to irrigate their crops.
On the Rio Grande, the picture is less rosy.
“The underlying drought remains unchanged,” said Phil King of New Mexico State University. King has his eyes on Elephant Butte Reservoir, the key storage reservoir on the Rio Grande. For all practical purposes, it remains empty.
“We went from 3 percent of storage to 4½ percent of storage. Big whoop,” King said.
“I am concerned that a lot of people think the drought is over, and it so does not mean that,” King said.
The storm has been unusual in a number of respects, weather and climate experts said.
The most important characteristic has been its persistence, said David Gutzler, a climatologist and professor at the University of New Mexico.
“It’s just been stuck,” Gutzler said.
The result has been what amounts to a river of water vapor streaming up from the tropics, wedged between stable weather patterns to our east and west, Gutzler said. “The maps show a river of moisture,” Gutzler said.
That makes the pattern similar to a classic New Mexico summer monsoon rain event, but much more extreme, because of its persistence, Gutzler said.
Instead of isolated thunderstorms, the storm has produced widespread, continuous rain, according to Kerry Jones of the National Weather Service, because the plume of moisture in the upper atmosphere is much warmer than a typical monsoon flow.
“This is as tropical an air mass as we get,” Jones said. That makes the storm much more efficient at getting rain out of the clouds and onto the ground, Jones said.
In that respect, the storm is not unprecedented. Many of New Mexico’s historic floods have happened around this time of year, as the remnants of tropical storms spin up from the Pacific across Mexico and into the Southwest.
In terms of drought relief, one of the most important features may be the way the storm is moistening mountain soils heading into the coming winter, said Wayne Sleep, snow surveyor with the Natural Resources Conservation Service. One of the problems the last few years was the dry soil heading into the winter, which makes a bad foundation for snowpack and spring runoff.
Sleep said his weather stations in the high country had registered between 1.5 and 2 inches of rain through midnight Thursday.
While good, that still leaves the state’s major watersheds with just 70 to 80 percent of average precipitation for the water year, which ends Sept. 30.