This would have saved her life. As would basic survival gear like a light tent, a small stove, a bit of food, and a space blanket. Heading out in those temps without such equipment is just nuts.

Sounds like she had phone coverage, and they still couldn’t find her. I know my new phone has satellite coverage.
We have a Garmin I reach and use it when camping or hiking.
Since she fell, it may have been just not enough time to get to her.
In Wyoming each winter a few motorists will die from exposure when their car breaks down off the main roads. Those that stay with their car live. Those that go out into the blizzard to walk a few miles may die. In my field car I always carried food, water, a sleeping bag and blankets.
“There’s such a simple solution if you are out in the wilderness by yourself. My wife bought one for me (though, at times, I think she’d rather I left it behind).”
For a small monthly fee use T-Mobile’s satellite servicewith your smart phone.
Maps, texting and exploring apps.