A deep burial is when the subjects is buried deeper than can be reached with a probe strike. Subjects at these depths become much more difficult to successfully rescue, and their survivability becomes less than 20%.
All stages of an avalanche search become significantly more challenging in the case of a deep burial.
Searchers must recognize a deep burial situation in order to successfully apply strategies to overcome it. A deep burial is likely a relatively large distance minimum and a wide area of similar distance indication results from bracketing in a fine search. Many searchers in exercises doubt the large distance reading when they cannot get any closer, and may waste time continuing their fine search; however, the distance reading at close range is fairly reliable and accurate.
As soon as deep burial are suspected, rescuers must take quick actions to maximize the potential for successful recoveries. These actions include:
Pinpointing with a probe is not possible if the minimum read-out is greater than the available probe length. In this case, once the suspected burial location has been obtained, shovelers will need to move two meters upslope and clear away enough snow until a probe strike can be obtained. Once the probe strike has been obtained, shovelers can reposition downhill from the probe and begin shovelling
The recommended search technique for deep burials depends on the type of transceiver being used. Digital transceivers without analog mode should use the diamond method, whereas digital transceivers with analog mode should use the fine search in a circle method.
Digital Transceivers – Diamond Method.
Digital Transceivers with Analog Mode – Fine Search in a Circle Method.