Reminds me of what a friend told with his grandfather when he was cutting wood for a carpentry project with a handheld wood saw, it slipped out of his hand and, I guess on instinct, tried to grabbed before it fell, if I recall he got some nasty lacerations from catching it on the blade before switching it off.
So I can only imagine what it might feel working with something that cuts before you can even register the damage. That was a close call, especially with the momentum of your movement could have done some irreparable damage to your hand.
Reading that, seems you were fortunately not traveling too fast, as I can imagine traveling along, the sudden stop, falling over face first into the packed snow and just sort of enacting an image of your one foot being propped like a hand trying to pull excalibur from the snow.