If you fall down there’s no reason to stop to get back up. Here’s how to get back on your feet without losing to much speed.
To parctice it first make sure there is no one in your way! Then start by gaining a good speed or have a steep slope, throw yourself on your back, put your heels in the snow so your feet will point uphill and you are going down head first. Then put your hands over your shoulders (next to your head) lift up your legs and do a backwards roll, landing on your feet. Try to have one leg a bit further back when you get back on your feet so you don’t do another roll.