Boise-area residents were treated to the rare, but not unheard of, dose of September snow Tuesday morning, as the initial days of fall asserted themselves at higher elevations up toward Bogus Basin Idaho Mountain Recreation Area.
The area received about 2 1/2 inches that accumulated on roadways and the hillsides, according to the National Weather Service office in Boise, with the ski area’s summit topping out at 7,600 feet. The early snowfall is uncommon for this time of year, but far from unprecedented, meteorologist Les Colin said.
“It is a bit unusual to get a system in here that’s that cold, but not exceptional. It happens every few years in September,” Colin said by phone. “While it was raining at first, it became cold enough to convert over to snow.”
In fact, under the right conditions, the Bogus area has seen summer flurries before, he said. The earliest the Boise area’s higher elevations have received snowfall was Aug. 24, 1992.
Bogus wasn’t the only part of the state to see snow Tuesday morning, Colin said. Reports showed the Trinity Mountains, about 40 miles east of Boise as the crow flies, received roughly double Bogus’ total — about 5 inches — while Tamarack Resort saw 3-4 inches, he said.
— ITD (@IdahoITD) September 28, 2021
The McCall area, at about 5,000 feet of elevation, received just a dusting, Colin said.
“It barely covered the bushes. Mostly just wet snow, just slush,” he said. “It’s 5,500 (feet) where it actually accumulated.”
As the temperatures continue to drop in the Treasure Valley, residents around Boise can expect patches of frost early Wednesday and also possibly Thursday morning, Colin said.
Our average first frost date historically is Sept. 25. But in recent years it has moved into mid-October.
“Now that it rained, we’ll probably end up with some fog overnight, and colder this coming night,” he said.