Step on the ice and slide across the big sheet like a skating rink to get to the ladder use the rocks to help you change direction.
you get it in icefall cave on 4 island clear the ice to get to the ladder that will lead you to the HM waterfall.
If you laid the ladder flat on the ice and wanked on the ladder rather than the ice, then your weight would be spread over a much larger area than that of just your feet. It would then be less likely that you would break the ice yourself.
On four island, there is a cave. You must enter it and then climb the ladder. walk through another set of caves, sliding on lots of ice. in one of the item poké balls, the HM07 Waterfall can be found.
If you lay the ladder down on the ice then crawl along it, your weight is spread over a larger area and the ice is less likely to break. If someone is holding the ladder, it gives you something to pull yourself out with if it does break.
If you suspect the ice may be thin the ladder will distribute your weight across a larger surface.
It is in Island four.
Level 51.
you first have to get hm waterfall then you go in icefall cave up the waterfall then go in the ladder and there.
because its ice and ice is clear
Go into Icefall Cave on island 4. break the ice at the far north end of the room, go up the ladder, then break the ice at the bottom of that section. get off the ice to the bottom, go up the ladder, and there is hm waterfall sitting there. Your welcome!
go with ice, water, psycic, and dark. you will win.
it is in ice fall cave on 4 island