Avalanche Risk Classifications

Risk Classifications for Avalanches

Avalanche hazards are an inherent risk when skiing off piste so it is important to remain vigilant of avalanche hazards when skiing in uncontrolled areas. In Europe there is a European Avalanche Hazard Scale which uses a avalanche flag based system to warn of the dangers. The scale is set by the resort using data provided by Meteo France. Using a scale from 1 to 5, the hazard indicator classifies the immediate danger that is present from an avalanche. Before venturing off piste, you should make sure you have read and understood the available avalanche information for your area. Regular avalanche bulletins are provided by Meteo France, and English website Pistehors.com often provide up to date snowpack and avalanche information. The hazard scale gives an overall indication and does not mean that an avalanche will not occur. The following table outlines the flag based system and an introduction on how to interpret the avalanche danger.: Hazard Rating 1/5 - Low Stability: The snowpack is generally well bonded and stable Activity: Triggering is possible only with high additional loads[2] on a few very steep extreme slopes[4]. Only a few small natural[6] avalanches (sluffs) possible Off piste activities: Virtually no restrictions on off-piste & backcountry skiing Hazard Rating 2/5 - Moderate Stability: The snowpack is moderately well bonded on some[1] steep[3] slopes, otherwise generally well bonded Activity: Triggering is possible with high additional loads[2], particularly on the steep[3] slopes indicated in the bulletin. Large natural[6] avalanches not likely Off piste activities: Generally favourable. Routes should be selected with care Hazard Rating 3/5 - Considerable Stability: The snowpack is moderately to weakly bonded on many[1] steep[3] slopes Activity: Triggering is possible, sometimes even with low additional loads[2]. The bulletin may indicate many slopes which are particularly affected. In certain conditions, medium and occasionally large sized natural[6] avalanches may occur Off piste activities: Should be carried out by experienced individuals with significant avalanche training and those who posses understanding and evaluation of potential hazards. Certain steep slopes should be avoided Hazard Rating 4/5 - High Stability: The snowpack is weakly bonded in most[1] places Activity: Triggering is probable even with low additional loads[2] on many steep[3] slopes. In some conditions, frequent medium or large sized natural[6] avalanches are likely Off piste activities: Restricted to low-angled slopes; areas at the bottom of slopes may also be hazardous Hazard Rating 5/5 - Very High Stability: The snowpack is generally weakly bonded and largely unstable. Activity: Numerous large natural[6] avalanches are likely, even on moderately steep terrain. Extensive safety measures (closures and evacuation) are necessary Off piste activities: No off-piste or back country skiing or travel should be undertaken [1] Generally described in more detail in the avalanche bulletin (e.g.altitude, slope aspect, type of terrain, etc.) [2] Additional load:- High - e.g. group of skiers, pistemachine, avalanche blasting. Low - e.g. skier, walker [3] Steep slopes: slopes with an incline of more than 30 degrees. [4] Steep extreme slopes: those which are particularly unfavourable in terms of the incline, terrain profile, proximity to ridge, smoothness of underlying ground surface [5] Aspect: compass bearing directly down the slope [6] Natural: Without human assistance

last updated 23-Nov-2007