Don’t call it a ‘#drought’: #Climate scientist Brad Udall views #ColoradoRiver crisis as the beginning of #aridification — Steamboat Pilot & Today #COriver

Photo shows the Colorado River flanked by fall colors east of Glenwood Springs, Colorado. Photo credit: USBR

Click the link to read the article on the Steamboat Pilot & Today website (Sean Naylor). Here’s an excerpt:

The generous monsoon season along the Upper Basin of the Colorado River has been a relief to those who remember recent summers suffocated by wildfire smoke in the American West. But according to Brad Udall, senior water and climate research scientist at the Colorado Water Institute and director of the Western Water Assessment at Colorado State University, the relief we’re feeling now is a sign of bigger problems for years to come.

“Next year’s runoff will be really interesting to see what happens, it will be a test of this theory of depleted soil moisture,” Udall told a packed room at the Betty Ford Alpine Gardens Education Center on Aug. 19. The theory he referenced examines how the recent precipitation affects the trending drought conditions, drying reservoirs and the lowering state of the Colorado River…

No longer calling it a ‘drought’

Merriam-Webster defines “drought” as “a period of dryness especially when prolonged.” According to Udall, we are beyond treating the Colorado River crisis as something that will soon pass, or ever will.

“This isn’t a drought, it’s something else,” he said. “Myself and other scientists are trying to use a different term: Aridification.”

Aridification is defined as “the gradual change of a region from a wetter to a drier climate.” According to Udall, it also means “declining snowpacks, it’s earlier runoff, it’s a shorter winter, it’s more rain, less snow, it’s higher temps. It’s drying soils, it’s severe fires, it’s forest mortality, it’s a warm, thirsty atmosphere.” The atmosphere, and the role it plays in our water cycle, is part of the reason for Udall’s skepticism throughout a rainy August.

“This atmosphere, as it warms up it actually wants to hold more moisture. That’s part of also the driving force of why these soils are drier,” Udall said.

Enter rising temperatures, which make soil harder, plants thirstier and standing water evaporate more quickly, and the formula for runoff becomes offset. According to Udall, not only does a hotter climate affect the return we get from our water cycle, but it also explains why flooding can still occur, and even be exacerbated, in drought-stricken areas.

“This warm, thirsty atmosphere is why we get more floods, because when the atmosphere sets up to generate rainfall, it actually has more water vapor in it,” he said.

The extra water vapor is also problematic when calculating snow runoff, which is another issue state climatologists have been trying to decode in the face of shorter winters. “I want to talk about 85 percent of snowpack turning into 30 percent of runoff,” Udall said. “You’d think 85 percent snowpack would turn into 85 percent runoff or 60 percent, it doesn’t anymore … when the snow goes to melt, more of it goes into the atmosphere than runs off into the river.”

“Early season runoff is more nourishing and summer precipitation dries up quickly,” he added, “which is why low runoff in March and April isn’t remedied enough by summer precipitation, though it does help with the next year’s runoff.”

According to Udall, as temperatures rise and aridification evolves, the region will see its deserts grow as its most important river shrinks. “The world’s deserts are about 30 degrees north or 30 degrees south of the equator, this is a known aspect of how our climate system works,” he said. “Basically, we get high pressure that descends over thirty degrees latitude. What we think happens is when the climate warms, that high pressure actually moves upward, so in our case, the desert just to the south of us is moving our way.”


Udall also has a heightened sense of faith in how Colorado is managing its situation. “In general, Colorado of all the Western states has its act together more than any other state. Why is that? Because our water rights system is slightly different, and for better or worse, we put in place a system that has a whole set of separate water rights codes and attorneys that specifically practice in water and engineers that specifically practice in water … so we have records and data and court decrees, we know where our water is used, who owns it, how it’s used … and in that is a system that at least gives us the data to make good decisions.”

Brad Udall: Here’s the latest version of my 4-Panel plot thru Water Year (Oct-Sep) of 2021 of the Colorado River big reservoirs, natural flows, precipitation, and temperature. Data (PRISM) goes back or 1906 (or 1935 for reservoirs.) This updates previous work with @GreatLakesPeck.

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