Bugle
Bugle lets you register an activity, pertinent details (“Went for trail run at Snow Lake at 5 p.m.”), and the time you’ll be returning. If you fail to check in with the app by your self-appointed deadline, anyone tagged in your circle gets a text or e-mail. Get Bugle for iOS (free)
Rescue Kit
A simpler (and less reliable) version of a SPOT satellite beacon, Rescue Kit sends your cell phone’s GPS coordinates to rescuers and knows the EMS digits used by hundreds of countries. A built-in flashlight feature signals SOS in Morse code. Get Rescue Kit for iOS ($2)
First Aid and Emergencies
More than 130 videos explain how to cope with medical crises, from a sprained ankle to anaphylaxis. Of course, it takes longer to watch an informational video than read instructions. Consider First Aid a backup to your field guide. Get First Aid for iOS ($3)
RadarScope
Is that a storm blowing in? Check RadarScope for precise National Oceanic and Atmospheric Administration data on weather coming your way. Note: bone up on basic meteorology to maximize RadarScope’s utility. Get RadarScope for Android or for iOS ($10)