Frostbite is the medical condition where localized damage is caused to skin and other tissues due to extreme cold. Frostbite is most likely to happen in body parts farthest from the heart and those with large exposed areas. Dr. Norm Woods suffered frostbite when he lost consciousness in Antarctica. (SG1: "Frozen")
In an alternate timeline, when SG-1 gated to the Achilles, Dr. Daniel Jackson stepped on a weak floorboard and his foot submerged in subzero water. He suffered severe frostbite and had to have his leg amputated. (SG1: "Continuum")