Ice diving
Ice diving, as the name implies, is submerging oneself under freezing water. As most people would put it, ice dives are called 'danger' dives - and for a reason. Ice diving can bring serious risks to one's safety, because ice dives are confined and there's no immediate escape available (unlike in open water).
Now, why would anyone want to ice dive, despite all the hazards it could bring? Well, there are several probable reasons. It could be the thrill of experiencing a whole new world when immersed in freezing cold water. Also, far from the hustle and bustle of life on land, being under the ice can actually give divers a feeling of peace and serenity.
Unlike other dives where an advanced open water certification level is enough to assess one's ability to go deep in the water, ice diving requires more specialized training. In ice diving, a carefully executed dive plan with multifaceted set of instructions, special equipment, and a well-trained team are essential to ensure everyone's safety.
You have to wear a dry suit and thick underwear, prepare the appropriate equipment, break open a portion of the ice, slowly slip into the sub-freezing water, and carefully descend under the ice. Ice diving is not really simple-- in every sense of the word. It's rather 'technical,' because a lot of properly conducted procedures are necessary to avoid accidents.
Typically, basic adventure diving requires one to have at least a buddy when going deep underwater. Ice diving is different; a skillful dive personnel made up of a dive master, assistants, tenders, safety divers, and actual divers are needed.
Dive Master
The dive master is the leader and takes charge of the planning, organization, execution, safety, and coordinates them to the members. Thus, the dive master must be knowledgeable of the dive plan, the equipment and the techniques. He/she should also be able to work (or dive, for that matter) gracefully under pressure, especially when emergencies occur.
Safety Divers
Safety divers are the ones who respond during emergency situations - looking for a lost diver, for instance. They should always be ready with their equipment, so that when something bad happens under the ice, they can easily dive and go to the rescue.
Line Tenders
Line tenders, aside from being in charge of the safety line attached to the diver, also serve as the timekeeper. They are the 'middlemen' between the dive master and the divers, so he must know all the appropriate line signals.
Assistants
Assistants do tasks such as cutting the hole in the ice, preparing the equipment for the divers, keeping time, etc. They follow the dive master's commands and perform specific instructions assigned to them.
Actual Divers
Actual divers are considered the 'star' of the ice dive, although they can't be so without the rest of the team. Ice divers should be well-trained and must know the specialized equipment used. They should also know basic first aid, and correspond appropriately to other team members.
All these members should work together, fulfill their duties, and support each other throughout the dive. Each team member is valuable for a safe ice dive.