Drought conditions have worsened in Southwest Colorado, causing a string of record-breaking temperatures, irrigation shortages and decreased crop yields.
On Aug. 25, Montezuma County went from a severe drought to extreme drought, which covers nearly the entire Western Slope, according to the U.S. Drought Monitor. Extreme drought Level D3 – is the fourth-highest of five drought categories.
Then there is the record-breaking heat wave.
Cortez broke eight daily high temperature records in August and tied one, said Jim Andrus, a Cortez weather observer for the National Weather Service.
Aug. 16 and 17 had highs of 98 degrees, up from previous records of 95 degrees in 1951 and 96 degrees in 2002, respectively. The Aug. 18 high of 97 degrees tied the 2002 record.From Aug. 19 to Aug. 24, high temperatures came in at 97 degrees, 98 degrees, 97 degrees, 97 degrees, 98 degrees and 96 degrees, respectively. That tops previous records of 95 degrees in 2002, 96 degrees in 2019, 95 degrees in 2009, 93 degrees in 2007, 93 degrees in 2008, and 94 degrees in 1936.“These late-summer records were caused by a persistent high-pressure area over the Four Corners filled with clear hot air, allowing the sun to heat our deserts repeatedly,” Andrus said.
Farmers experienced 10% to 15% water shortages this year from McPhee Reservoir, said General Manager Ken Curtis of the Dolores Water Conservancy District. Allocations for full-service irrigators were at 19 inches per acre, down from the full supply of 22 inches.
The 380,000-acre-foot reservoir will be drawn down to its 151,000-acre-feet inactive pool.
Project irrigators, Montezuma Valley Irrigation Co., the Ute Mountain Ute Tribe Farm and Ranch and the downstream fish pool all shared in the water shortages.
Back-to-back years of limited monsoonal rains have left soils dry going into fall. Much of the winter snowpack melt was absorbed into the soil before making it to the river and reservoir.
This year’s saving grace was carryover supply in McPhee left over from the above-normal snowpack of last winter, Curtis said.
Unfortunately, there is no carryover storage for McPhee heading into this winter, and the soil has again dried out.
Yields were somewhat down for alfalfa, officials said, because the limited water supply was spread too thin or was concentrated on fewer fields, Curtis said.
Alfalfa for Montezuma and Dolores counties is harvested three times per summer and is marketed to dairy farms. Farther south, Ute Mountain Ute farms harvest alfalfa four times per year.
Soil moisture was below 50% of average for dryland farmers, said Gus Westerman, Dolores County Extension agent.
Yields for winter wheat, which is planted in fall and harvested in early summer, especially suffered from the soil moisture deficit.
Pinto beans and the third alfalfa crop have not yet been harvested, and farmers are preparing to plant winter wheat.
“At this point, we are starting to get some afternoon rains, so hopefully that pattern will continue,” Westerman said.
Alfalfa crop prices were about $180 per ton.
The dry weather the past two years was attributed to persistent high pressure over the Four Corners, said meteorologist Tom Renwick of the National Weather Service in Grand Junction.
Monsoonal rains are hitting Arizona and New Mexico but are being blocked Southwest Colorado.
“The high pressure needs to shift toward the east toward the Texas Panhandle to allow the moisture from the Gulf of Mexico circulate your way,” he said.
Add to that a 60% chance for a La Niña weather pattern for the winter, which trends toward a more northerly jet stream and storm track that misses the Four Corners.
Why the persistent high pressure zone in the Four Corners area of the Southwest is a bit of a mystery to meteorologists, who have nicknamed it Triple R for “Ridiculously Resilient Ridge,” Renwick said. “It is happening more and more frequently.”
A cold front will arrive in Colorado beginning Monday, and drop temperatures into the mid-80s, then temperatures are expected to return to the 90s.