Ice diving is a type of penetration diving that takes place under ice. Because it is a particularly dangerous form of diving, divers need to wear exposure suits, hoods, and gloves to protect themselves from frigid waters; use a harness and rope to tether themselves to the surface in case they lose consciousness and must be hauled out; and train in correctly impacting the underside of surface ice in case of rapid ascent. Why should no more than two ice divers dive from the same hole at once? Discuss
Source: The Free Dictionary