Wyoming’s first real taste of winter is expected later this week, and it comes a month late for the more than 1,500 firefighters working to put down a pair of huge Wyoming wildfires that have burned nearly 170,000 acres in the northern part of the state.
It’s an eagerly awaited seasonal change after a warmer and drier-than-average fall overshadowed by the wildfires. The state will finally receive some relief by the end of the week.
Colder temperatures, rain and snow are in the extended forecast.
“It looks like a sure thing that the change will be arriving here at the end of the week,” Cowboy State Daily meteorologist Don Day said.
Fire Extinguishers
While the seasonal change from summer to fall is always anticipated, there’s a particular urgency this year with the intensity the Elk Fire in the Bighorn Mountains, which has burned about 90,000 acres, while the Pack Trail Fire in Bridger-Teton National Forest has burned nearly 78,000 acres.
Both fires still volatile and dangerous, with the Elk Fire at 27% containment and the Pack Trail Fire at 0%.
“I certainly think the Elk Fire and the Pack Trail Fire will see enough snow to help a lot with the fire activity,” Day said. “Everybody wants numbers, but talking about that this far out is just foolhardy. But I'm very confident that the mountains will get snow.”
Day wasn’t sure if the incoming weather would be enough to extinguish either fire, but expected snowfall and a significant drop in temperature should help firefighters. And there’s more to come after that.
Called It
For weeks now, Day has told Wyomingites to hold out until Oct. 18 for the change to winter. Judging by this week’s extended forecast, he was right.
Historically, the third week of October is the wall where Wyoming's unseasonably warm falls end. Day observed that the incoming winter weather system aligned with the Cowboy State's historical precedent.
“History is on our side,” he said. “By the third week in October, the daylight changes more rapidly, and the colder air builds. Eventually, you can’t stop it, and fall will get here. You usually don't see it delayed past the third week of October.”
The timing is almost perfect. The first snowflakes could fall over northern Wyoming by Thursday night, but Friday (which is Oct. 18) is when the statewide shift begins.
That said, Wyoming is a big state. While every corner of the Cowboy State will feel and see the change, Day said it won’t happen everywhere overnight.
“We have to divide this up a little bit,” he said. “The event for the state is going to be from Thursday through Saturday, but it will affect those northern and western areas first, then the eastern and southern parts of the state last.”
When And Where
The “event” will start in Wyoming’s mountain passes sometime between Thursday night and Friday morning. Day anticipates winter weather conditions in every mountain pass in northern, central and southeastern Wyoming by Friday.
“Powder River Pass, Burgess Junction, Togwotee Pass, Teton Pass, South Pass and the Beartooth Pass are going to have winter driving conditions by Thursday night and into Friday,” he said. “All the mountains will get accumulating snow by Saturday.”
“Accumulating snow” is the crucial phrase in Day’s assessment of the incoming weather system. The snow that falls this week will establish the foundation of Wyoming’s seasonal snowpack.
“We'll start to see some showers developing in the western border counties of Wyoming as early as Wednesday evening and Wednesday night,” he said. “We're going to see rain and snow break out across Yellowstone on Thursday and into Jackson, Star Valley, and down into Evanston on Thursday night. That should also get into places like Sheridan and Buffalo.”
Once the system hits northwest Wyoming, it’s expected to split and slowly drift eastward. From late Friday through Saturday, eastern and southwestern Wyoming should receive rain and possibly snow.
“Snow will get into the southern passes, like the Snowy Range and Battle Mountain Pass by Saturday,” he said.
While the mountains are certain to get snow, Day believes there’s enough strength in the incoming system for snow to fall in the lower elevation areas of northern Wyoming. Whether it’ll stick is another matter, and he’s doubtful it will.
“I think there's a really good chance that people (at the lower elevations) are going to see snow,” he said.” But when we've been as warm as we've been, and the ground is still warm, there will be some melting of the initial round of snow. It’s too hard to talk about accumulations, at least today.”
Abrupt Anticipation
Day wants Wyomingites to know the incoming winter weather system will be an “abrupt change” for the entire state. He hopes everyone prepares themselves accordingly.
“We should focus on the abruptness of the change,” he said. “A lot of hunters are out in the high country chasing elk, and they've had no weather to deal with at all. It’ll be a much different situation around the campfire by Thursday and Friday in many areas of the state.”
Anyone driving over mountain passes should be cautious and anticipate hazardous winter weather conditions. Day believes it’s still too far out to predict how much snow will fall during the four-day period, but it’s likely to be significant.
Day isn’t speculating beyond Saturday. The National Weather Service anticipates a “rebound” of warmer temperatures next week, but Day believes it’s still too early to tell.
“When you get a change like this, there's always going to be a rebound,” he said. “The question is what the extent of the rebound will be and how long it will last. I certainly don't see us getting in the deep freeze and staying there for weeks on end, but we've got to change the pattern first.”
Andrew Rossi can be reached at arossi@cowboystatedaily.com.
