Since he mostly seems to do North America it`s definitely a global common style. Piste maps seems to have been looking this way since 1970. Take a look at the 1970 map here https://skimap.org/SkiAreas/view/987 or any other place in the world. That said, obviously all artist have their own style and technique.
I used to also love piste maps as a kid, and still go skiing a few times per year. One of the best activities I know. Outdoor, exercise and spectacular views for a whole day. What a dream!
I used to also love piste maps as a kid, and still go skiing a few times per year. One of the best activities I know. Outdoor, exercise and spectacular views for a whole day. What a dream!