Apple Watch Series 3 can track skiing and snowboarding
Thanks to watchOS 4.2 apps like Slopes, snoww, Squaw Alpine, Snocru and Ski Tracks can now accurately report metrics like vertical descent, distance, number of runs, average speed and calories burned thanks to the built-in altimeter which can develop elevation.
More importantly, this information is gathered and reported towards a user's fitness performance. Being able to track calorie burn, run count, and speed make use of hardware like the altimeter elevation readings, accelerometer and GPS.