Emergency crews raced into the rugged backcountry around the Crimson Dawn area on Casper Mountain on Sunday after a side-by-side rolled, seriously injuring multiple people and leaving at least one woman reportedly without a pulse when rescuers reached her.
A Life Flight helicopter was called as deputies, firefighters and medical personnel converged on the remote area between Casper and Muddy mountains.
“We have one female on top of the side-by-side,” a responder relayed over emergency dispatch radio. “She is not breathing. No pulse.”
Nearly a day later, much about the crash remains unknown.
The Natrona County Sheriff’s Office hadn't responded to Cowboy State Daily’s requests for additional information as of publication, leaving the identities and current conditions of the people involved unclear.
That includes whether anyone was killed in the crash, and if so how many fatalities there were.
However, Natrona County Coroner James Whipps told Cowboy State Daily on Monday afternoon that “families have been notified” in relation to the crash.
“I am releasing no further information at this time,” he added.
‘She Is Not Breathing. No Pulse.’
The Natrona County Sheriff’s Office issued its first public statement about the crash at 6 p.m. Sunday.
Deputies and Fire-EMS personnel were “currently on scene of an ATV accident involving multiple individuals with serious injuries in a remote area between Casper Mountain and Muddy Mountain on the east end,” the agency reported.
“This remains an active emergency response,” the sheriff’s office added.
Dispatch information provides a more precise starting point for the response, listing the incident at Casper Mountain Road and South Crimson Dawn Road on Casper Mountain.
Radio traffic from Sunday afternoon also referred to responders being in the area of the “Crimson Dawn accident with injury.” A Life Flight helicopter had accepted the call with an estimated 23-minute arrival time.
Then came a more ominous report from the scene.
“We have one female on top of the side-by-side,” a responder said. “She is not breathing. No pulse.”
Radio traffic indicates responders were concerned about moving the woman because of the position and stability of the side-by-side.
The recording does not establish what happened to her afterward or the condition of the other people involved.
‘Never Heard So Many Sirens’
The emergency response was noticeable from elsewhere on Casper Mountain.
A man who said he was camping at Beartrap Campground posted to social media about the crash as emergency vehicles poured into the area Sunday.
“There is a horrible side-by-side accident on Crimson Dawn,” he wrote. “We are camping at Bear Trap and have never heard so many sirens!”
By Monday morning, the sirens were gone and the mountain was quiet again.
Cowboy State Daily drove the roads between Casper and Muddy mountains, documenting the isolated country where rescuers had been working hours earlier.
Signs on Casper Mountain point toward East End Road and Crimson Dawn Park in one direction and Muddy Mountain Junction in another. One sign puts Crimson Dawn Park 1.9 miles away and the Muddy Mountain junction 3.6 miles in the opposite direction.
Beyond the more developed portions of Casper Mountain, roads wind through sagebrush-covered hills and stands of timber. Pavement gives way to gravel and dirt, while smaller two-tracks disappear into draws and across open country.
Official Wyoming geographic descriptions identify East End Road as Natrona County Road 506 and place it along the Casper Mountain area near the north entrance to Crimson Dawn Park. Circle Drive Road, County Road 505, runs farther south toward Muddy Mountain.
The landscape provides some perspective on why the Sheriff’s Office characterized Sunday’s operation as a response in a “remote area.”
Authorities have not publicly identified the exact location where the side-by-side rolled or said what caused the crash.
Buddy Disappears
The rollover also apparently sent a small dog running into the mountains.
A white miniature schnauzer named Buddy was reportedly riding in the side-by-side when it rolled.
A notice circulated through a Casper pets lost-and-found Facebook group Sunday asking people in the area to watch for him.
“Missing dog goes by ‘Buddy,’” the post says. “Was involved in the side-by-side accident this evening by muddy mountain area.”
The post described Buddy as friendly, but cautioned that he could be skittish because “he was in the side-by-side when it rolled.”
Another person sharing the notice said the dog ran away after the crash and was roaming somewhere in the mountains.
Cowboy State Daily reached out Monday to people connected with the family seeking an update on Buddy and asking whether people were actively searching for him but did not receive a response.
It was not known Monday afternoon whether Buddy had been found.
Fatal ATV Crashes In Wyoming
Sunday’s crash comes amid a relatively small but recurring number of fatal ATV crashes in Wyoming, although authorities have not confirmed if anyone died in Sunday’s rollover.
As of Monday, the Wyoming Department of Transportation's 2026 fatal-crash map showed two fatal ATV crashes elsewhere in the state. The Casper Mountain rollover was not displayed in the database.
One of those deaths happened nine days before Sunday’s crash.
On Aug. 28, 58-year-old Robert “Bobby” Harris was killed in an ATV rollover on Sharp Nose Road near Riverton. The state crash report says the ATV was traveling south when Harris failed to negotiate a right-hand curve, left the road and rolled.
Harris was not wearing a helmet, and speed was listed as a possible contributing factor.
Nationally, crashes involving ATVs and other off-highway vehicles continue to kill hundreds of people each year. Federal safety officials urge riders to wear helmets and protective gear, never carry more passengers than a vehicle is designed for, avoid paved roads and never drive an off-highway vehicle while impaired.
Kolby Fedore can be reached at kolby@cowboystatedaily.com.
