An active week in Summit County’s backcountry ended Saturday with the death of a 49-year-old Cache County woman near Whitney Reservoir in the Uinta Mountains, authorities say.

According to Summit County Sheriff Dave Edmunds, “it was just a terrible mistake.”

Edmunds said the woman, who was riding a snowmobile, died after falling about 100 feet from a ridge. After bystanders attempted to administer CPR, medical responders declared the woman dead at the scene Saturday around 2:21 p.m., Edmunds said.

“She just drove straight off the cliff. She didn’t even know it was coming, it looked like,” the sheriff said, adding that the snowmobile also fell off the ledge. “There were some pretty traumatic injuries she took a nose dive and hit some rocks.”

Based on interviews with her spouse and the nature of the area in which she was sledding, deputies determined the victim was an experienced snowmobiler, Edmunds said. He did not release the women’s name pending notification of family members.

“This was just a horrific tragedy that may or may not have been prevented,” he added.

Each year, Summit County Sheriff’s Office Search and Rescue volunteers respond to many accidents involving snowmobiles, Edmunds said.

“We get snowmobile fatalities pretty much every year,” he said, adding, “we have more people here and that just, statistically, is going to mean that we’re going to have more accidents.”

Edmunds advises novice snowmobilers to be familiar with their machines and their surroundings.

“Know how powerful your machine is,” he said. “They’re capable of doing things maybe that the rider is not capable of doing.”

Meanwhile, the Park City Fire District responded to two snowmobile crashes last week in western Summit County, Fire District spokeswoman Tricia Hurd said.

Firefighters were dispatched Friday evening to White Pine Canyon after a man crashed his snowmobile into a tree, Hurd said, adding that he was taken by ambulance for treatment in Salt Lake.

On Feb. 22, two people were injured around 1:56 p.m. when they crashed their snowmobile into a tree near Pine Cone Ridge, about five miles into the western Summit County backcountry, Hurd said.

The driver suffered the most serious injuries and was airlifted for treatment to University of Utah Health Sciences Center, she said, adding that the passenger, who sustained less significant injuries, was transported for care in an ambulance.