So far winter is missing in action

Jason Stuart
Sunday, January 10, 2021
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The City of Glendive Public Works Department took advantage of continued warm weather to tackle several projects at Whipkey Park last week. Among the work completed was tree trimming and mulch replacement in the playground area. Hunter Herbaugh photo

December 2020 was one of the driest Decembers in Glendive’s recorded weather history, as the entire region remains stuck in an unusually warm, dry weather pattern for winter.

The total recorded precipitation for Glendive for December 2020 was just 0.02 inches according to the National Weather Service. That ties the month for the third driest December since recordkeeping began in 1893, equaling the totals of December 1991, 1987 and 1952. The driest December on record for Glendive was 1913, when not one drop of precipitation was recorded.

Snowfall for the month was also severely lacking. Glendive recorded just 0.1 inches of snow for December 2020, whereas the historic monthly average is 3.6 inches.

For the entire year 2020, Glendive’s precipitation clocked in at over three inches below the historic annual average. The total recorded for the year was 10.11 inches, ranking 2020 as the 21st driest year since record-keeping began. The annual average precipitation for Glendive is 13.55 inches.

Total snowfall for 2020 in Glendive was actually a bit above average, with 22.9 inches recorded for the year, whereas the historic average is 19.9 inches. However, the lion’s share of that fell in the winter and early spring months at the beginning of the year, with almost nothing in the way of meaningful snowfall since the end of October.

December 2020 was also unusually warm for Glendive, but to what degree, the weather service cannot say. According to Brad Mickelson, a meteorologist with the weather service’s Glasgow station, the official instrumentation at the Glendive water plant has been out of commission for the last several months due to the ongoing construction at the plant. Mickelson said due to that, the weather service unfortunately has no temperature data for Glendive for the past few months and was unable to cobble together any viable data from any other sources.

The culprit behind the unusually warm, dry winter so far is a jet stream that just can’t make it down from Canada to allow cold arctic air and storms over the region before it bumps into a stubborn ridge of high pressure that pushes the colder air and storms off to the east, Mickelson said. It’s a pattern he said has repeated itself over and over again for the last couple of months now.

“That northern jet stream just doesn’t have enough time to get storms here before it moves off to the east, and that just seems to be a recurring theme this season,” Mickelson said. “So we get occasional bouts of cold and some snow, but it’s just a passing glance. For now, it’s a repeated pattern of warm and dry weather, with storms being shunted off to the east far too quickly.”

It’s also a weather pattern that forecasters weren’t really expecting for this winter.

That’s because the weather service has identified a La Niña pattern in the South Pacific for this winter season. Typically, a La Niña leads to colder, wetter conditions for winter across the northern plains. But that hasn’t been the case so far this winter.

“We’ll still see what the rest of the winter does, but it’s not holding true to that typical (La Niña) pattern,” Mickelson said.

He added that, despite the current conditions here in Eastern Montana, the weather service is not yet concerned about the potential for drought conditions later this year. For one, he noted that the La Niña pattern is still there in the Pacific, and while the last couple of months have been unusually warm and dry, there’s still the distinct possibility that the La Niña could really assert itself over the next couple of months and bring those colder, wetter conditions with it. He also noted that while Eastern Montana has been unusually bereft of snow, the mountain snowpacks which feed Montana’s rivers are overall doing well.

“The mountains are getting plenty of snow over there in western Montana,” Mickelson said. “They’re doing pretty good in the mountains.”

However, the federal Natural Resources Conservation Service put out a press release earlier this week sounding some alarm over mountain snowpacks due to an extended dry period in December across most of western Montana’s mountain ranges, which caused the estimated snowpack levels to decrease across many monitoring locations.

While many of the monitored mountain snowpacks remain at or close to historic averages, scant mountain snowfall in December did not help the situation. For the Yellowstone River basin, the Upper Yellowstone snowpack is doing well at the moment, at 96 percent of normal, but the basin received just 59 percent of its monthly average snowfall for December. And while the Upper Yellowstone basin itself is fairing fine overall, the Yellowstone’s major tributaries are in much worse shape vis a vis the snowpacks which feed them. The snowpack for the Bighorn River basin is currently at 83 percent of normal, per NRCS data, while the Tongue River basin snowpack is at 86 percent of normal and the Powder River basin snowpack sits at just 74 percent of normal.

However, while the NRCS is showing some concern, with the La Niña still out there, they noted in their press release that it’s too soon for real alarm, as conditions could very quickly swing the other way.

“You don’t have to look far back in time to find a winter where early season snowpack totals weren’t looking good in certain parts of the state,” Luke Zukiewicz, a NRCS water supply specialist said in the press release. “Just last winter, snowpack totals in many river basins in western Montana along the Idaho border were below normal, only to have the weather patterns change and improve conditions before we got to runoff.”

“We’ll still see what the rest of the winter does, but it’s not holding true to that typical (La Niña) pattern,”

Brad Mickelson, NWS meteorologist