Ice diving

Ice diving is a type of penetration diving where the dive takes place under ice. Because diving under ice places the diver in an overhead environment typically with only a single entry/exit point, it requires special procedures and equipment. Ice diving is done for purposes of recreation, scientific research, public safety (usually search and rescue/recovery) and other professional or commercial reasons.

The most obvious hazards of ice diving are getting lost under the ice, hypothermia, and regulator failure due to freezing. Scuba divers are generally tethered for safety. This means that the diver wears a harness to which a line is secured, and the other end of the line is secured above the surface and monitored by an attendant. Surface supplied equipment inherently provides a tether, and reduces the risks of regulator first stage freezing as the first stage can be managed by the surface team, and the breathing gas supply is less limited. For the surface support team, the hazards include freezing temperatures and falling through thin ice.

Whether ice diving inherently constitutes technical diving is debated within the recreational diving community. For the professional diver it is a high risk environment requiring additional safety measures.

Ice diving is a team diving activity because each diver's lifeline requires a line tender. This person is responsible for paying out and taking in line so that the diver does not get tangled, and for rope signal communications with the diver. Professional teams will also require a stand-by diver and diving supervisor

Under some circumstances a guide line can be used as a reference for the divers to find the hole after the dive or in an emergency in a similar way to cave diving or wreck penetration instead of a lifeline. In these cases the divers should be competent in procedures for diving with a guideline.

Polar diving experience has shown that buoyancy control is a critical skill affecting safety.

Typical procedure for a scuba dive under ice:

Since diving under the ice takes place in cold climates, there is typically a large amount of equipment required. Besides each person's clothing and exposure-protection requirements, including spare mitts and socks, there is basic scuba gear, back-up scuba gear, tools to cut a hole in the ice, snow removal tools, safety gear, some type of shelter, lines, and refreshments required.

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