Temperature swings, entrenched drought worry forecasters across Colorado, Midwest

Candace Krebs
The Ag Journal
Mountain snowpack is running behind normal for virtually all of the state, which also means snowmelt and stream-flow will likely be diminished this spring. The drought in Colorado and the Southwest is being blamed on a La Nina weather pattern that appears to be strengthening rather than receding, leading to expectations of another dry spring and summer ahead.

Traumatic as the recent Siberian Express was for some regions of the country, a bigger concern to Colorado State Climatologist Russ Schumacher is the increasing frequency of extreme temperature swings that have hit the state recently in late spring and fall.

“If something like this is going to happen, this is the time we would expect it,” he said of the recent arctic surge that plunged all the way to the Gulf Coast with disastrous consequences.

“We had one of these in 1989,” he added during an appearance at the Colorado Fruit and Vegetable Growers Association annual conference. “They are rare, but they do happen periodically.”

More worrisome to him are the cold outbreaks that have occurred in months like April and October.

“The last two years we’re had some incredibly unusually cold outbreaks in late October, which are very bad for wine grapes among other things,” Schumacher said. “Something similar to that is the big freeze last spring that devastated the peach crop. These are a little harder to sort out in terms of what’s happening, because they are happening amid really warm years.”

He’d like to have a better understanding of why the state has seen single digit temps in October, which he called “a really exceptional thing.”

“We are trying to get better answers as to how things might be changing in a changing climate,” Schumacher said.

Colorado Springs meteorologist and private weather consultant Brian Bledsoe raised concerns of his own during the recent Marshall Frasier Beef Symposium, hosted by the Colorado Livestock Association and held virtually this year.

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Shots of extreme cold are not unexpected at this time of year, Bledsoe said. However, the problem is crops like winter wheat that are already stressed by drought are more vulnerable to injury.

“We’ve seen this happen to the winter wheat in February, and it’s turned out okay, if we caught some timely moisture,” he said. “But right now the chances of that happening are less than average. So these cold fronts coming down can do some damage.”

Both experts said the drought’s grip was not likely to ease for several more months.

“The spring is looking pretty bleak right now,” Bledsoe said.

What winter storms have crossed Eastern Colorado consisted of “dry powdery fluff,” which provided little liquid content, Bledsoe said.

“We need that wetter snow,” he said. “But I think right now the deck is stacked against us.”

The culprit is a La Nina weather pattern, triggered by colder ocean surface water in the equatorial Pacific.

While the latest arctic blast couldn’t be predicted until a week to 10 days out, that’s not the case with the deepening drought. Bledsoe warned his audience a year ago at the symposium to start drought preparations.

The current La Nina has deviated a bit from its usual pattern, the forecasters said, but now appears to be settling in and creating a stronger signal.

Art Douglas, professor emeritus of atmospheric sciences at Creighton University, has described it as a “rebounding La Nina,” which he has said can be particularly calamitous for significant portions of the U.S., including the Corn Belt.

Bledsoe’s forecasting models showed drought persisting across Colorado and spreading east and north across the Central Plains through the spring, with little sign of relief until August at the earliest. “I would have to say the areas along the Palmer Divide and the I-70 corridor and further north probably stand a better opportunity of getting some relief,” he said.

To this point, it’s the southern mountains that have picked up more winter precipitation, Schumacher observed, but that will likely change.

“The central and southern mountains benefited in February, but going forward it’s the northwestern region of the state that has a better chance of catching some appreciable snow in the weeks ahead,” he said.

Speaking as part of a water and weather panel that concluded the CFVGA meeting, deputy state water engineer Tracy Kosloff said the Rio Grande Basin was winning the snowpack lottery so far this year, while further to the south and west, the situation is dire.

Stream-flow forecast for the Upper Rio Grande is 107 percent of normal, with snowpack close to normal. But stream-flow forecasts in parts of extreme southwestern Colorado are as low as 38 percent of normal, with snowpack currently at 86 percent of normal.

Projected stream-flows across the western third of the state are all expected to be at 50 to 70 percent of normal.

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Mountain precipitation, critical for irrigation and reservoir recharge, is so important in Colorado that resource managers and planners are looking to boost information beyond what snow telemetry stations and stream-flow gages can provide. During the CFVGA meeting, Laura Kaatz, a project organizer with Denver Water, discussed the airborne snow observatory project, or ASO, a new flight program aimed at adding high-resolution snow depth imagery to the mix of tools.

Such imaging would detail exactly how much snow is still left in the higher elevations at a specific point in time.

“We first talked about it at the 2019 Colorado Water Congress, and we still have a lot of questions to answer,” Kosloff said.

Among them: when should flights occur? What will the data look like? Who houses it and how is it maintained and shared? What value does it have?

A large coalition of industries and agencies are involved in the project and have already identified numerous potential applications, she said, from flood control to road maintenance to recreational applications.

A working group is meeting monthly to discuss how best to advance the project, Kosloff said.