I am a skier and technology entrepreneur. I recently developed, Plan Alerts, a notification service for outdoor sports and adventure travelers. This article explains how you can use timed notification services and other tools to assist friends and search & rescue personel in finding you if you get in trouble.
Plan Alerts is a simple but useful tool that enables you to "timebank" your plans. You describe your plans, contact information and communication protocol (more on this in a bit). You set a deadline and list a few contacts. If you fail to check in by your deadline, the system notifies your contacts, and sends a link that displays your plan along with your check in / location history up until your last contact. You can check in via mobile web (with auto location fix), text/SMS, or voice (you can even call in from a payphone to record a voice message to your timeline, if for example, you're stranded and your mobile is dead).
This by itself can be hugely useful in enabling friends, and if needed rescue personnel, to find you, and with a couple of extra steps you can further improve your margin of safety. Off the shelf two-way radios are very useful in "off grid" locations. Even though their range is limited, if someone knows your general whereabouts, they can get close enough to make contact, if they know what channel you are on and what time you'll be listening. A simple instruction like "I'll be on Channel 5 on the quarter hour" tells people what they need to know to make radio contact, and allows you to conserve batteries if needed.
You can also link your PLB (personal locator beacon) to your Plan Alerts account. When you do this, SAR personnel can view your plan and checkin reports using your beacon code.
We just launched the beta a few days ago, and invite you to test the service. So feel free to check it out, and spread the word.