The SPOT messengers are also an invaluable tool. I have been in areas so remote that even high power HAM radios have not been effective. Sometimes mountains and other terrain will block just about every type of terrestrial radio signal. In those situations only the SPOT GPS satellite messengers got through. You can send your location, send "I am OK" messages to family, or activate the SOS 911 message. The SOS feature requires a $12.95 per year membership with the Spot GEOS Search and Rescue service but its worth it.
