Hidden power only has a base power of 60. Another solution is to find another ground type move with 60 or higher. The only other move glaceon can learn that's a ground-attack move is dig. Glaceon is a hard ice type to learn ground type moves.
If you want, you could switch to a different Pokemon like glalie, which he can learn earthquake and bulldoze. He also has hidden power too. So, check it out.
Hope this answered your question! :)
