Cold front ushers in September
Storm dampens most of county; snow falls in higher elevations
By Keith E. Domke
Ranger Editor

The month of September came in like a lion as a one-two punch of inclement weather brought some welcome moisture to Fremont County. And as the system moved through the area plummeting temperatures along with it, the first frost and snow of the season were witnessed.
Officially at Riverton Regional Airport, just over a quarter-inch of rain dampened the area during the two days. During the first wave Sunday night and into Monday morning, only .01-inch of moisture fell before .25-inch was recorded during the day Monday. In downtown Riverton, the amount was slightly less as .23-inch was recorded during the two days.
“A strong cold front moved through the area from the Pacific Northwest and brought some moist, colder Canadian air with it,” National Weather Service Riverton office meteorologist Al Ross said Tuesday morning. “It was kind of a double-barreled system that brought two shots of weather. The first whammy came through late Sunday night followed by the second wave during the day Monday.”
As the cold front moved through the county over the Labor Day weekend, temperatures plummeted. On Sunday, the thermometer at Riverton Regional topped out at 78 degrees. On Monday, the high was 19 degrees cooler at 59. The normal high for this time of year is 82 degrees.
Monday’s low temperature was 38 degrees, but the mercury dropped lower than that during the early morning hours on Tuesday. Ross said it was 34 degrees in downtown Riverton Tuesday morning while the thermometer at Central Wyoming College read 35 degrees at about 6:30 a.m. Tuesday.
Frost was seen in places on the ground and on rooftops in and around Riverton at daybreak Tuesday and snow capped the higher peaks of the Wind River Mountains.
“We heard there was 2 or 3 inches of snow on Togwotee (Pass),” Ross said. “I’m guessing that elevations above 8,000 feet may have gotten a little snow.”
As the weather system moved through, strong winds accompanied it. A 44 mph gust was recorded at the airport on Sunday while a 54 mph gust was measured on Monday.
In areas north and west of Riverton, higher amounts of precipitation were recorded. Ross said about an inch of moisture fell near Cody and Powell. In Dubois, .55-inch fell during the two days with .37-inch falling on Sunday and another .18-inch on Monday.
Southwest of Riverton, amounts were lower. Lander received .17-inch of rain over the weekend while Hudson got .18-inch. Ross said he didn’t hear of any reports of snow falling in the South Pass area.
He did say, however, that seeing snow in the mountains this time of year has happened before.
“The timing of this storm isn’t all that unusual,” he said. “We can get a little snow at higher elevations this time of year.”
According to the 100-year Climate of Riverton report, the earliest measurable amount of snow at the lower elevation of Fremont County’s largest city was Sept. 6 when 3 inches of the white stuff fell in 1929. Traces have been recorded on both Sept. 8 and 9, 1962. No snow ever has been recorded in Riverton during July and August. The average first date for snow in the city is Oct. 22.
The weekend moisture helped keep precipitation totals above normal for the year. In Riverton, 6.79 inches of precipitation has been recorded at the airport in 2008, which is .61-inch above the 30-year average. In Lander, 10.49 inches of moisture has fallen, which is 1.15 inches above normal.
The forecast calls for a return to more seasonal temperatures. Highs on Tuesday were forecasted to be in the mid to upper 60s with a return to 70-degree temperatures expected Thursday. A 40 percent chance of rain is in the mix for Thursday. Lows should be about 40 degrees.