Let's say you're skiing in the backcountry, looking for some powder — but instead, you trigger an avalanche.
If you have an avalanche air bag pack strapped to your back, you just yank the cord. That deploys the air bag, which keeps you close to the surface and easier to dig out, says Andy Wenberg with Backcountry Access, one of several companies making the devices. When deployed, his company's version of the air bag comes out like wings.
"The whole idea when you deploy that thing in an avalanche is you're avoiding burial death," he says.