Storm produces record October snowfall

Nathan Oster

South Big Horn County, and in particular Greybull, Basin and Shell, appeared to get the worst of last week’s storm that brought an abrupt end to the fall.
Adam Dziewaltowski, a meteorologist at the National Weather Service’s Riverton office, said weather observers in both Shell and Basin recorded 10 inches of snowfall between Wednesday, Oct. 25 and Friday, Oct. 27.
Dziewaltowski said the NWS hasn’t had an official weather observer in Greybull since 2019, but imaging suggests that 6 to  8 inches fell, with some isolated areas receiving as much as 10.
“According to our records, which go back to 1951 and up until 2019, that would likely have been a record for the most October snowfall ever in Greybull,” he said.  On average, Greybull receives about seven-tenths-of-an-inch of snow in October.
“Some snow is expected that time of year, but this system brought a lot more due to the track of the storm as well as favorable jet stream dynamics that set up over that part of the state,” said Dziewaltowski.
He said it’s still too soon to tell what kind of winter it will be in SBHC.  “The Climate Prediction Center issued something a while back regarding the winter outlook that suggested a pretty strong El Nino effect,” he said. “Based off past records, those tend to be warmer and a bit drier in terms of precipitation.
“It doesn’t mean you won’t see snow, but there might be longer periods of warmer temps and drier conditions.”
Observer needed
Geri Swanson, coordinator of the Cooperative Observing Program (COOP) in central and western Wyoming, said anyone interested in becoming Greybull’s COOP observer may contact her at
All training, equipment and supplies are provided. It just takes a few minutes each day to observe and report the high and low temperature and any precipitation that may have occurred in the previous 24 hours.
The data collected is then used by the NWS and many other organizations across the state and around the world for producing and verifying weather and water supply forecasts and tracking droughts.
Volunteer observers have been recording daily weather at Greybull since 1951.
This all-volunteer program has been around since 1890 and presently has nearly 10,000 COOP observers across the nation and territories, with over 135 in Wyoming.
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