That level of accuracy would be hard to achieve. Most radio signals (eg. BTLE) don't travel well through water (eg. snow).
Additionally, if you've ever dug someone out in the field (or practiced doing so) it takes a lot of effort to move snow. Being within three meters isn't good enough.
"When I ride alone I can maybe go top to bottom in slightly under 20m but I'm flying and really pushing it the whole time, I wonder if the drone could even keep up in that situation (speed would be over 25mph almost the entire time)."
Where do you ski? 20 min at 25 mph implies an 8.3 mile long run.