Instructions
Go to Route 216. It's west of Mount Coronet and south of Route 217.
Climb to the top of the snowy ledge. The ledge is immediately north of the Mount Coronet entrance and extends several screens to the left.
Walk all the way to the far right side of the snowy ledge. You'll see a lump in the snow to the right of the last tree. This is TM13 Ice Beam.
Face the lump and press the "A" button. You'll receive Ice Beam.