Again, ski tracks. I managed to clock up 50mph last year, which surprised me. Many people on my trip had it and there was much apres ski comparison of speeds and distance.
There's also a bug in it which you can exploit. If you <pause> tracking it sometimes registers a much higher max speed than you have really achieved, though it sorts it out when you save the day's skiing. Then, if you change from kilometers to miles it changes the units but not the number - I have a screenshot which shows I broke 100mph, though in reality I did nothing like that.
I don't think I managed 26 miles in a day, well done to your 7 year old. I bet they didn't stop for many coffees...
There's one called Ski Report as well - add the resorts you're interested in and it will have weather, snow reports and webcam links. You can get it to alert you if any resort has fresh powder, though I don't bother with that, not being flexible enough to dash of to the slopes at a moment's notice.
Most resorts have their own apps too, though these are usually just commercial guides to shops, hotels and bars. Can be interesting if you don't know the place you're visiting though.