If you are on the move in the mountains while having no or barely any connectivity, then this app is for you! Basically it will warn you of sudden air pressure changes while being independent of altitude changes.
What is so special about this? Normally air pressure will change with elevation! So the app will use GPS altitude data to account for this by calculating a normalized air pressure value. It then watches the tendency of that pressure value over the previous 3 hours and warn on demand.
What does a sudden air pressure change indicate? Without going into details, it can indicate a change in weather to be expected.