As Wyomingites enjoy a spring spoiler of sunny 60-degree days this week, there’s apprehension in high places. With snowpacks already struggling, how much is too much when it comes to warm temperatures in winter?
Monday’s forecast was mostly sunny, with high temperatures around the Cowboy State ranging from the upper 30s to low 60s. Meanwhile, nearly every snowpack in the state is below historical averages and declining.
Even Cowboy State Daily meteorologist Don Day acknowledges current snowpack levels aren’t great.
In fact, Wyoming’s snow-water equivalent snowpack released Monday by the Natural Resources Conservation Service, range from 24% of the historical median in southeast Wyoming to 63% in Yellowstone.
Across the rest of the state, every snowpack basin is under 100% except for Uinta, where it’s 103% of median. The state’s central and northern mountains, however, are holding less water that normal, ranging from 85% in the Lander area to 51% in the Big Horns.
Even so, a lower than normal snowpack isn’t something to be too concerned about in late January, Day said.
“To use a sports analogy, we’re almost at halftime and the team is definitely behind,” he said.
But there’s more to the season than snow. Day sees a situation with plenty of ground to cover and plenty of time to do it.
“We’re concerned about the levels that we have now, but encouraged by what we see in the long-term trend,” he said.
Day understands the concerns of Wyomingites who are watching diminishing snow levels in their communities. His response is to look at the state’s history and see where everything old is new again, especially in winter.
“It’s the yin and yang of Wyoming weather,” he said. “I can go back in the historical record and show you some warm Decembers, Januarys and Februarys where we have periods of weather like we're experiencing now. It's very up and down, and this year is more up and down than we’ve seen in the past.”
Cyclical weather patterns, from unseasonable springtime highs to subzero lows, are standard for Wyoming winters. The diminishing snowpacks the state is experiencing now in late January grew significantly during the intense polar vortex of mid-January.
That’s not so unusual. That’s El Niño, long anticipated and finally acting as meteorologists have expected it to, Day said.
He said the next plunge on this winter’s weather roller coaster is already on the horizon, revealing itself in the state’s weekly forecasts.
“There's a weather pattern change that will really help the western U.S.,” he said. “There's going to be a lot of mountain snow from the Sierra Nevada to the cascades to the mountains of Arizona, Colorado, Utah and parts of Wyoming.”
He anticipates Yellowstone National Park and Jackson will start seeing an extended snowfall by late Thursday or Friday. The National Weather Service Office in Riverton calls for rain and snow showers in Jackson before 11 p.m. Thursday.
The next weather pattern should give western and southern Wyoming a big boost for snowpacks. However, northern Wyoming will probably be left wanting.
“I still think that the northern drainages of the state are going to be on the edges of the storms,” Day said. “There is help on the way for them, but the bigger gains will be made in the western and southern drainages.”
Can’t Take The Heat
Building snowpacks is always good news, but how much damage has been done? Day doesn’t deny the impact of the 50-plus-degree days, but said the trend needs to be sustained before it’s concerning.
“These warm spells negatively impact the snowpack at the lower elevations, where we start measuring the snowpack in the foothills,” he said. “The biggest reduction in the snowpack is going multiple days (with warm temperatures) where it's not snowing and not keeping up the pace.
Those warm spells tend to happen in March and April. However, the “yin and yang” of Wyoming weather means earlier spells aren’t unheard of, Day said, adding that the real alarms sound if the current snowpack amounts are at the same levels in a few weeks.
“If we're no different than when then where we are now in five weeks, the middle part of March, then I’d certainly be concerned,” he said. “But with the long-term trends we're anticipating, we should have opportunities to see increased precipitation compared to where we've been.”
Better Late Than Early
Despite the concerning numbers, the best snow of the season has yet to come. Once again, historical precedent leads Day to conclude that current snowpack levels are concerning after “the first half,” but the next half has always delivered the best results.
“The water content in the snow is really important,” he said. “The higher water content of the snow is later in the season. The bigger bang for the buck is not how many inches, it’s the water content.”
Day said three feet of snow in the Tetons in December or January might contain an inch and a half of water. But two feet of snow in March can contain up to four inches of water.
The best snow of the season comes late, adhering to another of Day’s oft-quoted mantras about Western winters.
“The driest months of the year are December, January and February,” he said. “And then, the wettest months go from March to June.”
A Good Water Year
Sizable snowpacks are enormously beneficial for Wyoming. However, an exclusive focus on the ups and downs of snowpacks is missing the forest for its admittedly essential trees.
Day said Wyomingites want more snow, but need a good water year. There’s more to that than the winter snow.
“A good water year in Wyoming is a good snowpack, from December through April, and a wet spring across the lower elevations into early summer, which is going to be March through June,” he said. “When you get both, you have a great year. When you have one or the other that suffers, you start to run some deficits.”
Day cites the 2022-2023 winter season as “a good water year” along the lines of what’s most beneficial for Wyoming. The current season hasn’t followed the same pattern, but several months lie ahead.
“I always tell people that Mother Nature always evens things out at the end,” he said. “We certainly have the opportunity to get really cold again before the winter is over. We still have a lot of winter left.”
Andrew Rossi can be reached at firstname.lastname@example.org.