When discussing rescues in avalanche accidents, mostly technology and innovation concerning avalanche beacons are brought up, while there is another location tool which is essential within a rescue team: the avalanche rescue dog.
Some history:
Avalanche rescue dogs date back to 1937, to the first documented rescue, when a kid buried by an avalanche was rescued by a non trained dog, who tracked the position of the victim by his own initiative, therefore enabling his location and rescue. Avalanche rescue dogs can be classified broadly as either trailing (and tracking) dogs or airscenting dogs. Tracking dogs use human scent as a reference (a single scent, from the missing person), having to discriminate the rest of scents; these dogs typically work on lead, and mostly keep their nose to the track to capture any scent molecule and particles from the victim. Beagels, Bloodhounds among others, are predominant breeds for these tasks. Airscenting dogs, on the contrary, are multitask and can specialize in different disciplines (collapsed buildings, avalanche and large areas).
“Airscenting dogs can take approximately 4 to 8 minutes to locate a victim buried by a 10.000m2, 1 to 2 meters deep avalanche.”
On the other hand, airscenting dogs do not keep their nose to the ground, instead, they raise their head to capture any human scent particles suspended in the air, particles within a virtual scent cone. They are capable of tracking a large area within a short period of time.
Airscenting dogs can take approximately 4 to 8 minutes to locate a victim buried by a 10.000m2, 1 to 2 meters deep avalanche.Using an airscenting dog, it is crucial to manage the search correctly and the handler must introduce the dog in the area facing the wind, which will cut the aforementioned cone, enabling the location of the victim in the shortest period of time. The optimal and most efficient method is to lead the dog in Z shape.
“Another essential quality in a rescue dog is courage: it is crucial that a dog is courageous in order to be exposed to danger without the external pressure of his guide, and to hold on to this situation, even when it goes against his survival instinct.”
Some specific breeds have optimal skills to work on avalanche rescue, such as German shepherds, Belgian Mallinois shepherds, Labrador retrievers, Golden retrievers or Border Collies
Rescue Dogs: skills and characteristics
A dog must meet ideal physical conditions and morphology for the task: a strong, agile, medium sized dog. Besides, the dog must have certain inborn qualities, such as a tendency to hunt (the desire to prosecute a prey), a tendency for prey (the desire to liberate its prosecution anxiety through the bite), and to search intensively (interest and persistence to find a prey). At the same time, he must have a sociable and balanced personality.
Another essential quality in a rescue dog is courage: it is crucial that a dog is courageous in order to be exposed to danger without the external pressure of his guide, and to hold on to this situation, even when it goes against his survival instinct.

Searching Human Scent:
The dog’s smelling system is designed to detect chemical substances around him, which exist in different concentrations and are transported through the atmosphere or deposited on surfaces. The rescue dog is trained to search an ensemble of substances expelled by the human body, whose origin and properties are very diverse.
We have to consider that during an actual search, residual scents may exist, either those from the rescue team members, from previously rescued victims, from the victims’ gear or from dead animals caught by the avalanche. An operational dog must discriminate these scents, although they can occasionally attract its attention, it shouldn’t mark them as hot spots; we name this “faux marking”.

“An avalanche dog, is not only used to locate, but also to discriminate and confirm the existence of possible victims.”
We should bear in mind, that snow is the surface where residual scents persist the longest, which makes the search harder for the dog. An avalanche dog, is not only used to locate, but also to discriminate and confirm the existence of possible victims.
An avalanche rescue dog marks a victim’s location through scratching and barking, in this order; when the dogs fails to attain the victim due to terrain difficulty, exhaustion or stress, he will start to bark.
Once the dog marks a real situation, the guide will come close and confirm with his probe the existence of a possible victim; then, he will reward the dog, discretely giving it the biter. In a situation with multiple victims, once the first victim is confirmed with the probe, the guide will resume the search of other victims with the dog, while the rest of the rescue team will use shovels to proceed with the victim extraction protocol. It is advisable not to urinate, eat or smoke, neither to remain seated in the working area. It is absolutely forbidden to play with the dog while it is at work; the rest of the rescue team and people in the area should totally ignore the dog.
The guide:
The dog guide’s profile must be that of a mountain specialist within a professional rescue team: the pair needs to be autonomous in this field, as in most situations, he will not rely on other colleagues to execute his function. Therefore, a good dog guide must be a good skier and he must have the appropriate physical and psychological training; he must have good knowledge of winter forecasting, snow science and meteorology, and a good training on mountain techniques.

Ivan Muñoz Bernabé (Fireman and dog guide at the Ribagorza-Huesca county in Spain, Avalanche Specialist)