NRC Publications Archive Archives des publications du CNRC Avalanche hazard evaluation and prediction at Rogers Pass Schaerer, P. For the publisher’s version, please access the DOI link below./ Pour consulter la version de l’éditeur, utilisez le lien DOI ci-dessous. Publisher’s version / Version de l'éditeur: https://doi.org/10.4224/20338093 Internal Report (National Research Council of Canada. Division of Building Research), 1961-12-01 NRC Publications Archive Record / Notice des Archives des publications du CNRC : https://nrc-publications.canada.ca/eng/view/object/?id=b6665547-1b3c-4797-8a3c-e226f730b565 https://publications-cnrc.canada.ca/fra/voir/objet/?id=b6665547-1b3c-4797-8a3c-e226f730b565 Access and use of this website and the material on it are subject to the Terms and Conditions set forth at https://nrc-publications.canada.ca/eng/copyright READ THESE TERMS AND CONDITIONS CAREFULLY BEFORE USING THIS WEBSITE. L’accès à ce site Web et l’utilisation de son contenu sont assujettis aux conditions présentées dans le site https://publications-cnrc.canada.ca/fra/droits LISEZ CES CONDITIONS ATTENTIVEMENT AVANT D’UTILISER CE SITE WEB. Questions? Contact the NRC Publications Archive team at [email protected]. If you wish to email the authors directly, please see the first page of the publication for their contact information. Vous avez des questions? Nous pouvons vous aider. Pour communiquer directement avec un auteur, consultez la première page de la revue dans laquelle son article a été publié afin de trouver ses coordonnées. Si vous n’arrivez pas à les repérer, communiquez avec nous à [email protected]. NATIONAL RESEARCH COUNCIL CANADA DIVISION OF BUILDING RESEARCH THE AVALANCHE HAZARD EVALUATION AND PREDICTION AT ROGERS FASS P. Schaerer This is a joint report of. the Department of Public Works and the National Research Council Internal Report No. 227 of the Division of Building Research Ottawa December 1961 The Trans-Canada Highway through Glacier National Park, British Columbia, was designed and constructed by the Federal Department of Public Works, Because the highway would have to cross numerous avalanche paths, the Department began, as early as 1953, preliminary observations on the snow cover, weather and avalanche conditions that would be encountered and in the winter of 1955-1956, established a regular observation program to provide the information required for the specification of the avalanche defences. In 1956, the National Research Council, in response to a request from the Department of Public Works, supplied some of the special instruments required for the observations. About that time, the Division of Building Research of the Council re- cruited to its staff a civil engineer trained in Switzerland. in road construction. The services of this engineer, Mr. Schaerer, were offered to the Department of Public Works. In 1357 he was seconded to that department and given the task of recommending to them the avalanche defence for the highway. Through Mr. Schaerer and valuable contacts with Dr. M. R. de Quervain, Director of the Swiss Federal Institute for Snow and Avalanche Research, the valuable experience of the Swiss was applied to the problem at Glacier. !Phe development of the avalanche defence for the Trans-Canada Highway through the park area, and the associated snow cover, weather and avalanche observations required for the specification of that defence, was the first project of its kind to be undertaken in Canada. It is probable that this project will serve as a model if similar projects should be undertaken in the future. A11 too often, the experience obtained in such work is not recorded in a form that will make it readily avail- able. The National Research Council welcomed the chance to assist in the program at Glacier and to have the opportunity to prepare such a record. One very important part of avalanche defence is the evaluation and prediction of the avalanche hazard. Although it was the responsibility of the Parks Branch of the Department of Northern Affairs and National Resources, to organize and operate this service after the Highvlray was completed, it was necessary to predict the character of this service in designing the over-all defence system. Furthermore, such a service had to be available during the period when the observations required for specifying the defence system were made, and while the de- fences and Highway were constructed. The experience obtained in avalanche hazard evaluation and prediction during that period, and the role that it plays in the over-all defence system, is recorded in this report. 'This report is one of a series reporting the work at Glacier. It represents singularly close co-operation between the Department of Public Works and the Division of Building Research, co-operation which it is a pleasure to acknowledge in this way. Ottawa Robert P. Legget December 1961 Director. TABLE OF CONTENTS TERRAIN 1. Climate Zone. 2. Snowfall. 3. Temperature. 4. Wind. AVALANCHES AT ROGERS PASS Periods of Avalanche Activity SOME FUNDUIENTAL CONSIDERATIONS TO THE AVALANCHE HAZARD EVALUATION AND PREDICTION The Testing Method The Analytic Method ORGANIZATIOII OF THE OBSERVATIONS Snow and Weather Observations Observations at Rogers Pass Summit and at Glacier State of the Weather Observations at Flat Creek and Stoney Credk Observations on Mount Abbott Special Observations Records Survey of the Avalanches Personnel CAUSES OF THE AVALANCHES Rupture Zones Climate Areas The Snow Cover The Snowfall Wind Temperature Spring Thaw Avalanches Special Avalanches AVALANCHE \ITARNING The Avalanche Hazard Forecast Highway Closures ANTICIPATED ORGANIZATION AND RESPONSIBILITIES OF THE AVALANCHE WARNING SERVICE Responsibilities of the Avalanche Warning Service Personnel Snow Cover and Weather Observations Effec-t of Avalanche Warning on Highway Traffic Avalanche Warning for Skiers Table of Contents (Contld) ACKNOWLEDGMENTS REFERENCES APPENDIX I: Selection of the Mountain Observatory APPENDIX 11: Equipment and Methods of Observations APPENDIX 111: The Weather Forecast APPENDIX IV: Mount Green Avalanche APPENDIX V: Crossover Avalanche THE AVAUNCHZ HAZARD EVALUATION AND PREDICT1 ON AT ROGERS PASS 2. Schaerer In the early 1950fs, consideration was given to the use of Rogers Pass as a possible route through the Selkirk Range for the Trans-Canada Higl~tvay. The pass, the lowest and shortest route through the Selkirlcs, is located between the towns of Golden and Revelstolce in British Columbia. The summit of the Bss is near the town of Glacier in Glacier National Park (pigs, 1 and 2). The discovery of the Pass by Major A. B. Rogers during his survey for the Canadian Pacific Railway enabled that company to complete the first railway link between Eas-tern Canada and the West Coast in 1885. The line through the 'Pass was used. until 1916 when it was abandoned on the completion of the Connaught Tunnel. The valleys associated with the Pass are narrow and have steep sides. Because of heavy snowfall in the area winter and spring avalanches are a common occurrence, In 1953, the Department of Pu3lic Ihiorlcs, responsible for the construction of tbe highway in Glacier National Park, began a study of the location of each avalanche site and the conditions under which the avalanches occur, Mr. N. C. Gardner was in charge of these observations, In 1956, when the decision was made to construct the higllv~aythroug-11 the Pass, the Department of Public 1,filorks established an avalanche observation station at Glacier. The observation program was enlarged to obtain the information required for the specification and design of the defence system. An avalanche hazard forecast routine was established for the protection of the avalanche observers, surveyors and construction crew, The National Research Council, through its Divisioil of Building Research, co-operated in the organization of the avalanche observation station. Initially, the National Research Council contributed information and apparatus for taking the necessary weather and snow cover observations; when the author joined the Snow and Ice Section of the Division of Building Research, the follv~vingresponsibilities were assumed: 1. To make recommendations on the type, location and design of the defence for each avalanche site, To assist in the organization and taking of the observations required for the recommendations, In April of 1957, the author was seconded to the Department of Public !Vorks and joined the avalanche observation station at Glacier on a full-time basis. During the winters 1957-1958 and 1958-1959 he was responsible for the snow cover, weather and avalanche observations that were made. Based on these observations and others taken prior to 1957, a defence plan was drawn up and reconmendations made for the defence at each avalanche site. This information is published in a separate report (1). The recommended defence plan included highway closure and control of avalanches with explosives. The evaluation and prediction of the avalanche hazard is therefore a necessary and integral part of the avalanche defence. The National Research Council had no responsibility for the organization of the avalanche hazard prediction and warning service required for the highway but it was necessary to anticipate the nature of this future service when establishing the defence for each avalanche site. It was considered that a record of the nature of the future warning service that had been in mind when