Rising temperatures, declining flows and the White River

Science and math tutor at Meeker High School examines records to produce a micro picture of the changing climate

by Allen Best

The Colorado River’s problems are broadly if perhaps superficially understood in the United States. The river in the 21st century has been woefully inadequate in delivering what had been expected when its flows were divvied up during the 20th century and the dams, canals and other infrastructure built.

The river and its tributaries may be the nation’s most high-profile demonstration of the impact of global warming.

Colorado’s White River is part of that story. The river’s headwaters lie in the Flat Tops between Meeker and Yampa in northwestern Colorado. The river flows past Meeker before joining the Green River in Utah. The Green, in turn, flows into the Colorado near Moab.

In total annual yield, the White River has averaged 560,000 acre-feet annually, according to a now probably outdated flow chart of rivers in Colorado. That’s a little more than a third of what the Yampa River delivers, although substantially more than the 400,000 acre-feet of the South Platte River.

The Colorado River dwarfs them all, delivering 4.5 million acre-feet at the state line (if there were no diversions).

But the White, like most of the other rivers, has been delivering less water. Bob Dorsett, a science and math tutor at Meeker High School and Stanford-educated physician, has documented the declines in a paper he distributed during November. The paper can be found here.

Dorsett’s findings follow a now familiar storyline. Temperatures on the Flat Tops have increased “significantly” since 1987. Yearly precipitation has decreased.

Total yearly runoff in the White River at Meeker has declined by about 70,000 acre-feet since record-keeping began in 1910. That, he points out in his report, represents a loss in water volume of about 14%.

Similar to what has been documented elsewhere, Dorsett found earlier runoff in the White River. In former times, not much was happening in April. Now, the White flows briskly with runoff then. On the other hand, flows have declined significantly in June and even more remarkably in August.

“September daily mean flow is decreasing dramatically,” he reports. “On this trend we can expect to see the river run dry in September in some years before the end of the century.”

Lesser summer flows result in potentially higher temperatures of the water, “possibly contributing to algae blooms and to fish stress,” because of reduced habitat for trout and other species, he said. The reduced flows also strain irrigation and municipal supply systems.

Dorsett based on his study, in part, on examination of temperature and precipitation measurements from two Snotel stations, one at Burro Mountain, elevation 9,400 feet, and the second at Ripple Creek, elevation 10,340, both in the area of the broad alpine plateau.

The two Snotel sites were established in 1987. Comparing their records from 1987-1992 and then 2020-2025, he found rising average daily mean temperatures, especially in mid-winter and late summer.

Precipitation has declined as temperatures have risen. Three of the last five years have been notably subpar. The aberration was 2023, when the snowfall was exceptionally deep. The runoff, however, was not exceptional. Exceedingly dry soils soaked up runoff and kept peak flows moderate that year.

The White River Basin was hammered hard by two major wildfires this past summer. The Lee Fire covered 137,000 acres before it was contained in mid-September, making it the fourth largest or fifth largest wildfire in Colorado’s recorded history, on par with the Hayman Fire southwest of Denver in 2002. The Elk Fire, also in the White River drainage, was somewhat smaller.

Dorsett’s work calls to mind a report from Colorado’s Western Slope in 2020 by Washington Post reporter Juliet Eilperin that carried this headline: “This giant climate hot spot is robbing the West of its water.”

Eilperin had stops at Orchard City, Palisade and Fruita, although none to the north. Nonetheless, the maps she assembled show the White River country to be very much in the red zone.

“This cluster of counties on Colorado’s Western Slope — along with three counties just across the border in eastern Utah — has warmed more than 2 degrees Celsius, double the global average, Eilperin wrote. “Spanning more than 30,000 square miles, it is the largest 2C hot spot in the Lower 48, a Washington Post analysis found.”

The National Oceanic and Atmospheric Administration data upon which that statement was made did not include Alaska and Hawaii for that time period.

On the White River, Dorsett’s takeaway is simple: “The river is changing. The trends are long-term and unmistakable. Understanding them is the first step toward adapting.”