I did not see the app but I read a big article about how they rely on GPS or phone service to pin point your location. Guess what you don't have when your buried under concrete like snow? If you said GPS and or phone service you are correct. I can see a HUGE lawsuit coming from this app or another like it.
They DON'T transmit or receive the standard 457MHZ signal that every beacon on the market in this world work on.