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Environment & Science

Montana Snowpack Building After Dry Spell, But Drought Still A Factor

Montana's most recent drought monitoring map, released January 7, 2021.
Montana's most recent drought monitoring map, released January 7, 2021.

Meteorologists last fall said Montana could be in store for a particularly cold and snowy La Niña winter. By late October, cold temperatures and record snowfall shattered regional records — but that wintery weather quickly gave way to much drier and mild conditions.

So what has happened to our winter, and what’s next?

Montana Farmers Union President Walter Schweitzer remembers that cold and snowy October weather.

“Forced us to start feeding the cows a little earlier than we wanted," he said.

Schweitzer raises cattle and runs a haying operation southeast of Great Falls near Geyser. He said November ushered in significant changes.

“We haven’t had a lot of snow in the last month or so," he explained.

According to the U.S. Agriculture Department's Natural Resources Conservation Service in Bozeman, November’s temperatures ran near to slightly above average in western Montana and well above average in the state’s southeastern corner.

The state’s southern tier received below-normal monthly precipitation. The National Weather Service tweeted out last weekend that Billings has not had a colder-than-normal day since December 14. That is 27 days and counting.

All of this flies in the face of the commonly-held perception that La Niña weather patterns always bring cold and wet winters to Montana. Missoula National Weather Service Meteorologist Dave Noble explained one didn't always equal the other.

“La Niña is not the only factor that goes into the global climate system," he said.

As an example, Noble points out that the Pacific Ocean's jet-stream air current has been particularly strong recently.

“The jet is just screaming across the Pacific, and then it’s breaking and a lot of the energy is going north," he said. "They’ve been getting slammed with heavy precip events on the British Columbia Coast into Alaska.

"By the time they make it over us, they're bringing southwest winds ahead of it, they're bringing that warmer air up, keeping us mild. We’ve been stuck in that pattern for a while.”

According to NRCS-Bozeman, the last week of November marked the beginning of a prolonged dry period for almost all of Montana’s mountain locations. That dry spell led to statewide declines in snowpack, especially at the low to mid-elevations.

NRCS Water Supply Specialist Lucas Zukiewicz said a handful of active storms right before the new year helped replenish that important mountain snowpack. 

As of Jan. 1, snowpack varied widely across Montana. In some river basins along the Rocky Mountain Front, snowpack was above normal for this date. It was near to slightly-below normal in other Western Montana river basins.

One notable exception — Southwest Montana, which missed out on those early season snowstorms.

“The areas, right now, which are sticking out are really the Jefferson River Basin, kind of more specifically, the Ruby, the Upper Beaverhead, parts of the Madison, as well as the Gallatin river basins," Zukiewicz said. "So that whole corner of Southwest Montana has a snowpack which is below normal for the state.”

The Montana Department of Natural Resources and Conservation’s Michael Downey coordinates the state’s drought monitoring and reporting efforts. He said about 34% of the state falls into drought categories ranging from D1 to D3.

“D1 being moderate, D2 severe, and D3 extreme drought," he said. "The extreme drought is down in the southeastern part of the state.

"And then there's quite a bit of D0, which is abnormally dry. So 63% of the state is still in some kind of a drought status or warning. And that’s the thing that concerns me most.”

National Weather Service meteorologist Dave Nobel did some digging and found eight previous La Niña winters in the Missoula-area that produced relatively dry Novembers and Decembers.

"Four of those had above-normal snowfall for the season. Four of those had below-normal snowfall for the season. Six of those seasons had fairly snowy Januarys. You know, it’s pretty hard to nail down exactly what’s going to happen.”

But the weather and drought experts who spoke with MTPR agree: There is still plenty of time for snow totals to recover before the start of spring runoff. According to NRCS Bozeman, only about 35-45% of the seasonal snowpack typically accumulates at mountain locations by Jan. 1.

The long-range weather forecast suggests a large-scale pattern shift is possible starting later this week or early next. What does that mean specifically? For the moment, forecasters only describe it as more typical wintery weather. 
Copyright 2021 Montana Public Radio. To see more, visit Montana Public Radio.