Ice causes erosion to take place. Ice forms in a crack and causes the rock to break. Erosion: when ice melts, liquid water preforms the act of erosion by carrying away the tiny rock fragments lost in the split. The specific process(the freeze thaw cycle) is called frost weathering or cryofracturing. Temperature changes can also contribute to mechanical wearying in a process called thermal stress. But I’ll get into that for a different question ;)