Jen Norvell has been hiking since she was 5 years old. She grew up in the Catskills and lived in the Adirondacks. The retired U.S. Army officer once ran a program that took juvenile delinquents into the backcountry. She knows wilderness first aid.

“I’m not the one who needs to get rescued,” she said. “I never thought I’d be in a situation where I couldn’t take care of myself.”

That changed in a split second last week when the 49-year-old Ouray woman slippe...