I jus did this, too! ^^

Scurry around and find a blackbelt to fight. To his right is a rock you can move with strength. Do so and go down the ladder. You'll arrive in an Ice-Cave-Esque area, with Nevermeltice, and some other junk. You can find Snorunt around here, they're uncommon, and the one I caught was at L28.

Happy hunting!