Effective probing is critical for effective and fast recovery. When probing, the following techniques should be followed:
Professional responders must be familiar with and practice all probing methods. Different methods may be used depending on the stage of the response and whether or not the subject is wearing a functioning transceiver.
Spot Probing. Performed in likely burial areas (trees, rocks, and depressions) when transceiver searching is not an option.
Grid Probing. Performed after a successful transceiver search.
Position Probing. Performed after a probe strike is made. Knowledge of the subject’s position is desired to facilitate shovelling and to more efficiently access the subject’s airway. This operation must be done quickly because time is of the essence.
Three-Holes-Per-Step Probing. 3HPS is an organized probing method to search for subjects who do not have functioning transceivers. It may also be used in conjunction with other search methods if the avalanche area is large enough and there are enough rescuers on the scene. Leadership is crucial in organized probing. The line leader may be separate from the line, or if required to participate in the search, should be positioned in the centre where their voice will be clearly heard by everyone.
If two complete passes of the search area are unsuccessful, then probers should realign shoulder to shoulder (25cm grid spacing) and continue probing in a fine search. The fine search requires a probe master and strict marking to ensure optimal coverage. If the fine search is unsuccessful, a grooming machine may be used to gently remove the top 1m of snow.
Slalom Probing. Slalom proving is another organized probe-line technique used to search for subjects without functioning transceivers. This method requires that each rescuer be responsible for searching a 1m-wide strip of the avalanche debris. Probing is done walking in a “slalom” pattern across the strip. Studies show an increase of up to 50% in the speed of this method compared to the 3HPS method.
The International Commission for Alpine Rescue (ICAR) has adopted standardized flagging to help reduce the potential for errors by ensuring consistency between different search groups. Flagging also helps to ensure an efficient rescue by maintaining a clearly laid out and organized scene.