When Jill Shockley Siggins woke up at 4 a.m. Monday, she saw sleet falling on the windows of her home along the South Fork of the Shoshone River, 47 miles west of Cody.
Later that morning, she was alarmed that the residue left on her windows and vehicles proved challenging to clean.
“It felt sticky, like talcum powder,” she told Cowboy State Daily. “I could pick up a layer off of my vehicle before I tried washing it off. It wouldn’t wipe off with water. It was very sticky.”
Siggins found some success using vinegar and Dawn liquid detergent, but struggled to remove the layer of whatever it was from her home and vehicles. That's the same remedy many recommended to get geothermal mud off vehicles parked too close to Steamboat Geyser in Yellowstone National Park.
Siggins has experience washing stubborn layers of stubborn skyborne substances from vehicles. She worked at Cody’s Fremont Motors and cleared ashfall from the Mount St. Helens eruption of 1980 and the Yellowstone fires of 1988. When she shared her experience on social media, hundreds of people reported similar struggles in Cody, Powell, Clark, and Greybull.
“This dust is different, and I’d say it’s worse than the fires or Mount St. Helens,” she said. “And it isn’t dust from the Buffalo Bill Reservoir. I’ve lived in the country my whole life and know what that’s like. This substance is out of this world.”
Wyoming’s meteorologists believe there is an earthly explanation for northwest Wyoming’s mud-covered morning. After a windy weekend, everything’s coming back to earth.
“I’ve seen this before, usually during fire seasons,” said Cowboy State Daily meteorologist Don Day. “There was plenty of wind in areas where the snow’s melted off, and that’s likely what happened.”
It’s Rainin’ Mud
The best explanation for the muddy morning in northwest Wyoming was clouds of dust mixing with moisture from an incoming winter weather system carrying plenty of moisture from the Pacific Ocean.
“This was the leading edge of the next Pacific storm coming in,” Day said. “It’s the preamble of the next system coming in.”
Monday’s moisture followed an incredibly windy weekend. The highest wind gusts – 107 mph – were recorded in South Pass’s Red Canyon on Saturday and Sunday.
The wind stirred up a lot of dust on the exposed ground in northwest Wyoming and eastern Idaho, sending dust clouds high into the air. When precipitation moved in and started falling, the dust condensed in the water droplets and fell with it.
“A lot of dust has been picked up locally and downwind from Idaho,” said Jason Straub with the National Weather Service (NWS) Office in Riverton. “Now that we've got some precipitation, the dust is being pulled out of the air, producing a lot of dirty, dusty rainfall.”
Despite the number of people caught off-guard by the dirty rain, Straub called this a “fairly common occurrence,” especially after high-wind events. More importantly, a trip to a car wash should be enough to remove most of it.
“It’s pretty much just mud,” he said.
Mud-covered cars in Cody after a Monday morning mud drizzle. The windy weekend turned up clouds of dust that fell back to earth with Pacific precipitation from an incoming winter weather system that will bring lots of moisture to most of Wyoming on Tuesday. (Andrew Rossi, Cowboy State Daily) 
The windows of Jill Siggins' home in Cody are covered in mud after a windy rainstorm. (Courtesy Jill Siggins) 
Mud-covered cars in Cody after a Monday morning mud drizzle. The windy weekend turned up clouds of dust that fell back to earth with Pacific precipitation from an incoming winter weather system that will bring lots of moisture to most of Wyoming on Tuesday. (Andrew Rossi, Cowboy State Daily) 
The windows of Jill Siggins' home in Cody are covered in mud after a windy rainstorm. (Courtesy Jill Siggins)
More Moisture Incoming
Only northwest Wyoming had to deal with a muddy Monday morning, but the entire state will benefit from the incoming moisture. However, as is usually the case with systems like this, your results may vary.
“The heaviest snow is going to be centered along the I-90 corridor,” Day said. “There could be five to 10 inches of snow in Sheridan, Buffalo and Gillette, stretching into the Black Hills. From there, amounts will vary depending on where you are.”
Cody and the northern half of the Bighorn Basin could see up to six inches between Monday night and Tuesday morning, and Rock Springs and the western end of I-80 might see four to eight inches by Tuesday evening.
This snow won’t be muddy, but it will probably create a lot of mud as it falls. Straub said temperatures will dip into the 20s, but the ground will still be pretty warm when the snow falls.
“Anything that does fall is going to mostly melt,” he said. “Western and central Wyoming should expect snowy, slushy conditions, plus blowing snow, especially overnight into Tuesday morning.”
Meanwhile, southeast Wyoming might see an insignificant amount of snow – two inches at most.
“Accumulations will be on the lighter side, but that could cause some travel difficulties for those commuting on Tuesday,” said Shelby Fuller with NWS Cheyenne. “It’ll be breezy, but snowfall rates shouldn’t cause too much of an issue. The main concern will be slick road conditions.”
Regardless of how much snow falls across Wyoming, every section of the state will get some moisture from the winter weather system. That’s always welcome during the wettest months of the year.
“We are trying to get as much moisture as we can, so every drop counts,” Fuller said.
Siggins is hopeful that northwest Wyoming gets the whole six inches of snow expected. That should help clean things up.
“I’ll look forward to the snow washing that stuff off,” she said.
Andrew Rossi can be reached at arossi@cowboystatedaily.com.
