2. Emergency! Alert Panic Button (Android | Free)
While not as comprehensive an app as StaySafe, the Emergencty! app for Android is effectively the same thing. The user can specify emergency contacts to send the alert to including a link to google maps showing their location via SMS, Facebook, Twitter or email. It also records 15 seconds of audio as a possible way to help the authorities locate you. Another good one for traveling alone or outdoor sports.
3. Life360 (iOS & Android | Free)
Life360 has gotten big press for it's wide financial backing and growing number of users (more than 12 million at the time of this post). While there has been some backlash accusing the company of enabling "helicopter parents", the designers have taken a step toward giving more power to those being tracked, such as adding a check-in button. There's still plenty of tracking functionality for the concerned parent or guardian and the added ability to see nearby safe and unsafe areas. Using the app has the added benefit of being able to track those without smartphones.
4. Personal Safety (Android | $1.99)
While we would normally consider a wide range of functions a feature, in this case the personal safety app's swiss army knife of personal safety alerts borders on the paranoid. That being said it's certainly the most comprehensive solution we've seen on either platform. Weather, crime, allergies and even flu levels are included. Sadly there's no zombie apocalypse or alien abduction threat levels so you'll have to look elsewhere for those, but if you find yourself in a variety of possibly unsafe situations with your 'droid in your pocket, Personal Safety might be your app.
5. Weather Alert USA (iOS | $3.99)
While just a weather app, events like Katrina have this kind of threat to body and property pretty well seared in our minds. A well timed weather alert can save you, your family and possibly your stuff (quick, pack up the sound system! oh, and the kids!). The app is just like a weather radio or TV alert that you're used to, down to that horrifically annoying noise. Be sure to set up your alerts properly when you buy it, unless you like surprise frost alerts at 4 am with the urgency and noise of a tornado drill.