What are the Best Climbing Apps for a Smart Phone?

I carry a smart phone in case of emergency. Are there apps that might be useful, since the phone is already in my pack? —Anonymous

My favorite is Offline Topo Maps from Gaia. This app costs $4.99 but is worth it. You download the area where you’ll be traveling while you have an Internet connection; then the maps work out of network. It has a pretty good touch-screen GPS —great for backcountry day climbs, or as a back-up GPS on longer trips. If you travel a lot, the Mountain Project app ($5/year) is nice; again, you download route descriptions and then access the info out of cell range. Outside the U.S., the Converter+ app (free) helps with all sorts of things—I find the currency and metric-to-English conversions most useful. Remember to preserve battery life in the backcountry by shutting off your phone, or at least turn off Wi-Fi, cellular, and data roaming.

—Marc Chauvin is an IFMGA-certified guide based in North Conway, N.H. (chauvinguides.com).