Preventing, or stopping yourself from falling too far during a climb when you don’t have the use of a belay rope or another person is called self-arrest, and it is a very important skill to develop. There are quite a few techniques that are taught depending on the school of ice climbing presented, but the overall basic technique is basically the same.
First, how you perform a self-arrest depends on how you are sliding down the slope. If you’re slipping so that your face and stomach will hit the slope first, it’s important to make sure that the pick of your ice pickaxe is facing away from your body and towards the snow. As you’re falling, place the ice pickaxe diagonally across your body so that the pickaxe head is by your shoulder, and the spike is near your hip. Then, once you hit the slope, arch your back and press the ice pickaxe into the slope with your body weight, making sure to spread your knees apart and protect your face from the other end of the pickaxe head by turning away. If done correctly, this technique should slow your descent rapidly to a standstill, where you can adjust your footing as needed.