Snow + fetlocks = trouble. The melting snow sticks to the long hair of the fetlocks, forming icy balls that pinch and twist. I'm sure all that ice next to skin has got to be uncomfortable as well. Solution? Clip off the long hairs that attract the mess, then apply a little Vaseline. The Vaseline, an oil-based product, repels water and prevents the snow from sticking.
Ta-da! No more ice balls.
You don't have to use a clippers-- a plain old scissors will work fine. You're not looking for a clean shave, just to get rid of the shaggy stuff. Pro-tip: invest a couple of bucks in a pair of safety scissors. That way, you'll never have to worry about poking a horse with the pointy tips of regular scissors. This is especially invaluable if your horse doesn't like standing still.