Positioning of rescuers: quick measurement of distance between shovelers.   Working in sectors on the snow conveyor belt: snow is transported with paddling motions.   Clockwise rotation is initiated by the front person: job rotation maintains a high level of motivation and minimizes early fatigue.   Buried victim is first seen: more rescuers are needed at the front, and the snow conveyor belt only need be kept partially running.   Careful work near the buried victim while some shovelers aggressively cut the side walls to adapt the tip of the V to the real position of the victim.   Interface to organized rescue: more space shoveled only after medical treatment of victim has started.

Overview

To excavate an avalanche victim takes by far the greatest amount of time during a rescue. When considering the flow between beacon search and transport of victim, the gap between a successful hit with the probe and care for the air pocket constitutes a missing link in the otherwise tremendously well-structured knowledge on rescue. Development of the “V-shaped conveyor-belt approach to snow transport” started in 2004 and was tested quantitatively in the spring of 2007 during a large field test. During this test the uncoordinated approach to shoveling was measured as well.

The environment during the test

A site near the field laboratory of the Norwegian Geotechnical Institute in western Norway was chosen. A spring snowpack with high density and hardness proved to be a realistic simulation of dense avalanche debris.

The “victims” were two bags normally used to carry firewood, sewn together and filled with straw. The texture of those bags closely resembled the stickiness of ski clothing to snow, therefore making it necessary for the rescuers to completely remove all snow before being able to transport the victims. In order to avoid a loosening of the debris around the victims, great care was taken to dig small shafts during burial. In addition, the snow around the victims has been left to re-freeze on the surface during one night. The next day the snow around the victims was stomped down layer by layer. The day after – therefore after three days – the victims were ready to be rescued.

Three different burial depths were used (1m, 2m and 3m) in 2 different slope angles (flat = 0-5 degrees, steep = 20-25 degrees).

Choice of rescuers

Using the V-shaped conveyer-belt approach, coordinated shovelers transport snow centrally downhill.

Experienced rescuers adapt shoveling technique to suit individual strengths, such as coordinated sideways snow transport.

After first visual contact with a buried victim , the front team continues to work together.

All “rescuers” were chosen carefully. With ages between 19 and 39, they represented the age group that statistically most often becomes avalanche victims. Men and women from three different countries were chosen; the ensuing language challenges simulated to a certain degree the communication problems that often occur between rescuers who speak the same language with increased stress levels during a real incident. The call for volunteers read: “four-day avalanche course free of charge, including food, including active participation in a two-day digging experiment.”

The digging experiment

In order to eliminate exhaustion as cause for potential mistakes, the digging experiments were spread over four days. After digging for a short while, the rescuers were assigned a less physically challenging learning module, after which another section of work with the shovel was completed.

Collection of data

The hole's depth increase was measured every 30 seconds. After every excavation the hole and excavated volume were carefully measured. The time measurements included first visual contact with the victim, head (airway) access time, first visual of the full body, lifting of the victim, and positioning the victim outside the burial site. Documentation included high-definition pictures as well as real-time video. An instructional video is available.

Challenges for an efficient and careful excavation

During companion rescue a single probe is normally used to locate the victim; this can result in little knowledge about the positioning of the body. On one hand a quick approach to the airway is necessary; on the other hand a certain amount of snow needs to be transported to facilitate efficient removal of the mass of snow. Furthermore, rescuers should be positioned so that the buried subject and possible air pocket are not endangered. The V-shaped conveyor-belt approach to snow transport is the answer to this challenge.

How to work efficiently over a long period of time

One major requirement of an effective rescue is to maintain the efficiency of the rescuers at a constant level. So the question was: Why do rescuers get exhausted so quickly when they apply uncoordinated shoveling? We wanted to avoid having the rescuers fatigue easily when shoveling as this results in longer breaks and therefore an undesired slowdown of active resources. We noted that rescuers achieve rapid exhaustion due to holding an ergonomically challenging position over a long period of time. In response, we found that clockwise rotation of rescuers every four minutes in the V-shaped conveyor belt method avoided this early exhaustion. The idea of job rotation has been used in industrial production for a long time.

An additional challenge to efficiency is the method of snow transport. Vertical lifting of snow constitutes one of the least efficient methods – despite maximum use of strength, snow still does not get transferred away from the victim. The bigger the lift with the shovel, the bigger the amount of snow that can fall off the shovel. A paddling motion, with which the rotation of the whole body can be utilized as opposed to just using the arms, is much more efficient and results in a bigger mass of snow to be transported (measured in liters/rescuers/minute). Methods that suggest steps be dug for snow transport or methods suggesting kneeling or sitting positions are just as inefficient.

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