Don’t Call It a ‘Drought’: Climatologist Brad Udall Calls Colorado River Crisis the Start of Aridification

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Colorado River at Glenwood Canyon.
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The generous monsoon season along the upper Colorado River basin has been a relief to those who remember recent summers choked with smoke from wildfires in the American West. But according to Brad Udall, senior water and climate researcher at the Colorado Water Institute and director of Western Water Assessment at Colorado State University, the relief we’re feeling right 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 said to a packed room at the Betty Ford Alpine Gardens Education Center on 19 august. The theory he referred to examines how recent rainfall affects trending drought conditions, the drying up of reservoirs and the lowering state of the Colorado River, which is the main source of water. for more than 40 million people spread across seven western states, more than thirty Native American tribes, and Mexico.

Udall’s relationship with the Colorado River goes beyond the simple focus of his studies. He grew up along its shores and worked as a river guide in his early years. He also comes from a long line of influential family members in the management of the river for over a century. His father, former congressman Mo Udall, fought to channel water from the river to Arizona. His uncle, Stewart Udall, was the former Home Secretary who opened the Glen Canyon Dam. And his great-great-grandfather, John D. Lee, established Lees Ferry in Arizona. “The Udalls are, in fact, Lees,” he told the crowd.



With a litany of maps, peer-reviewed studies, and side-by-side chronological photographs of depleting reservoirs, Udall’s presentation, titled “Colorado River Crisis: A Collision of 19th Century Water Law, 20youth Century Infrastructure and a 21st Century Population Growth and Climate Change,” broke down the intricacies of the pact that establishes water rights between these states, while establishing the environmental agitators that have formed and grown since the pact was was concluded in 1922.

Stop calling it a “drought”

Merriam-Webster defines “drought” as “a dry period, especially when prolonged.” According to Udall, we are beyond treating the Colorado River crisis as something that will pass soon, or never pass.



“It’s not a drought, it’s something else,” he said. “I and other scientists try to use a different term: aridification.”

Aridification is defined as “the gradual change of a region from a wetter climate to a drier climate”. According to Udall, it also means “lower snowpacks, earlier runoff, shorter winter, more rain, less snow, higher temperatures. It’s the drying up of the soil, it’s serious fires, it’s forest mortality, it’s a hot and thirsty atmosphere.

The atmosphere and the role it plays in our water cycle partly explain Udall’s skepticism throughout a rainy August.

“That atmosphere, as it gets warmer, actually wants to retain more moisture. That’s also part of the driving force behind why these soils are drier,” Udall said.

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

“That hot, thirsty atmosphere is why we have more flooding because when the atmosphere settles down to generate precipitation, it actually contains more water vapour,” he said.

The extra water vapor is also problematic when calculating snow runoff, which is another issue that state climatologists have tried to decode in the face of shorter winters. “I’m talking about 85% snowpack turning into 30% runoff,” Udall said. “You would think that 85% snowpack would turn into 85% runoff or 60%, that’s not the case anymore…when the snow melts, there’s more of it left in the atmosphere than in the river.”

“The early season runoff is more nourishing and the summer rainfall dries up quickly,” he added, “which is why the low runoff in March and April is not sufficiently corrected by the summer rainfall, even if it helps the next year’s runoff”.

According to Udall, as temperatures rise and aridification evolves, the region will see its deserts expand as its most important river narrows. “The world’s deserts are about 30 degrees north or 30 degrees south of the equator, that’s a known aspect of how our climate system works,” he said. “Basically, we get high pressure that goes down to more than thirty degrees latitude. What we think is happening is that when the climate gets warmer, that high pressure actually rises, so in our case, the desert just south of us is heading towards us.

Brad Udall presents “Colorado River Crisis: A Collision of 19th Century Water Law, 20th Century Infrastructure and a 21st Century Population Growth and Climate Change,” to a packed house at the Betty Ford Alpine Gardens Education Center on Friday, August 19, 2022.
Sean Naylor/Vail Daily

Every trend is going “in the wrong direction”

As Udall showed a graph depicting rainfall levels over previous decades, showing their decline over the past 22 years, the occasional splash of rain occurring outside during the presentation seemed even less significant.

“2018 is the worst year for upper basin rainfall since 1895, 2020 is in the bottom 10, 2021 in the bottom 20…all of those years are really in the lows,” he said. “So the whole precipitation pattern has shifted down.”

Udall then factored in the rising temperatures. “Up 3 degrees Fahrenheit since 1970…and crucially, not a single year after 1999 is below the 20th century average, and we’ll never see a year below the 20th century average again.”

These two trends of low precipitation and high temperatures make the situation along the Colorado River more critical than ever.

“If you took the worst period of the 20th century, the worst period of 22 years, if it had only repeated itself instead of the last 22 years that we had, our reservoirs would be 55% full, not 27 %. It would be concerning, but it wouldn’t be the crisis it is,” he said.

While history has repeated itself before, Udall’s presentation suggested not betting on it. “We must anticipate even weaker flows than what we have seen in the past 22 years. We didn’t put a number on it, we just said a ‘reasonable worst-case future,’” he said.

“Let’s see some experiments”

As the Colorado River’s water supply dwindles, demand continues to grow. Population growth has not only filled major cities that depend on the river’s water, it has also spurred the rise of new towns along its basin, further complicating debates over water allocation. “Now we have to think about how to roll back some of that…we have no control over supply, so we have to reduce demand,” Udall said.

While Udall argues that Colorado has been exemplary in managing its water allocations with increased efforts in engineering and global communications, there are lessons to be learned from the innovations happening across the basin.

A member of the crowd asked about desalination efforts in California, and Udall acknowledged desalination as “part of the solution, but it’s a tiny part of the solution.” citing Australia’s efforts over the past decades that have accompanied their own respective challenges, one of the most important being the cost. “Farming (farming) will never be able to afford it,” he said.

Udall then pointed out the reintroduction of beavers in some places as another potential part of the solution. “There’s been some interest in reintroducing beavers to places in the High Country to set up these wetlands where you store water, and you get these sponges that slowly release water later in the year…if it would work, I don’t know, but it’s another idea along the same lines,” he said.

As for switching to crops that use less water, that too has its own set of hurdles. “Crop change is actually quite complicated, it requires new agronomic knowledge, new production and marketing, new labor and new equipment…you need a collective of people in the same area growing new things,” Udall said.

Udall mentioned Arizona’s use of aqueducts and Las Vegas’ innovative water recycling system, while maintaining those conservation efforts, and a a more conscious use of water consumption in our daily livesare always the best ways to save time.

“I just feel like we have to meet the demand for this system and I don’t know how to do it with the resources we have,” he said.

A view from the top

Colorado’s upper basin position will give Colorans an advantageous view of what works and what doesn’t as states in the lower basin face more pressing scenarios in the years to come.

While speaking to a host of ski resorts, Udall was aware of what this crisis means for our favorite winter activity and the industry surrounding it.

“Here’s the good news for people in Colorado: so it’s higher and colder in the middle of the continent,” he said. “If you had a ski area in the Sierras right now, when it wants to rain in the winter, I’d be worried. Anywhere you have a maritime climate close to the ocean and it used to be 31 (average degrees) in the winter and now 33 you have a huge problem. Colorado is higher, drier and colder and will stay that way. So these ski areas will do better than ski areas anywhere else. It also rains in the winter here – and it shouldn’t be – so that’s good news and bad news.”

Udall also has increased confidence in how Colorado is handling his situation. “In general, Colorado of all 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’ve put together a system that has a whole set of separate water rights codes and lawyers who practice specifically in water and engineers who practice specifically in water…so we have records and data and court decisions, we know where our water is used, who owns it, how it is used…and in this is a system that at least gives us the data to make good decisions.

“More than any other state, we’re better off…but it’s still not great.”

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