著者

Ryan D. Mark

出版者

信州大学農学部

雑誌

信州大学農学部AFC報告 (ISSN:13487892)

巻号頁・発行日

no.2, pp.35-65, 2004-03

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This comparative and case study, undertaken from May 2000 to February 2004 at locations in Washington, Alaska and finally Nagano, Japan, focuses on a winter thoroughfare called the Kamikochi Norikura Super Rindo(herein: Forest Road) in the Azumi Village, which has been accosted with avalanche incidents and accidents for a number of years despite large investment in avalanche protection measures. In Japan, problems that are associated with winter both mountain travel safety to outdoor recreation safety are in many ways characterized by the issues which surround the risk management planning, use and management of this road. The problem in Azumi is of how to reduce the avalanche hazard along the Forest Road. In this paper, as an introduction and general overview in support of the ideas and concepts brought up body text, the current situation of avalanche work worldwide and in Japan is presented. One tendency seen in Japan is for heavy reliance on permanent measures such as the 88 snowfences constructed on the Forest Road at a huge expenditure(153,353,000JPY) in Azumi over the last 23 years. Avalanche forecast-ing is also rare, as demonstrated by only recent inclusion snowfall parameters for road closure purposes in Azumi. In North America and Europe, active avalanche control, which is the process of artificially releasing avalanches through explosive use, is popular as a temporary measure. Such protocol is often used to and complement to permanent measures such as earthworks or snowfences which redirect or reduce velocity of snow flow. In Switzerland alone 10,000kg explosives are used annually in avalanche control work. For the purposes of this study, operating models of bombing routes using hand-deployed charges and bomb trams which carry explosives to avalanche start zones as seen on field trips and inspected in Highway departments and ski areas in the US are proposed as a solution for the Forest Road in Azumi Village, Nagano, and investigated with respect to applicability, safety of use, legality, etc. The only legally hand-deployable charge in Japan, and major topic in this study is a new product called ACE(Avalanche Control Explosive) the research of which is facilitated through elementary on-snow testing. Through the course of this study it became evident that underlying the snow safety issue are issues in forest policy, road use planning, measure selection and funds appropriation. Delving further, it became clear that village and higher government may not have had access to a full range of internationally accepted options in the search for answers to problems of avalanche hazard reduction. In Azumi this inaccessibility to technology has resulted in expensive construction of inadequate permanent protection measures. Assuming that a program including active control could be formally made available to road managers at an attractive price, either deployment of charges by hand or light cableway would be suitable, albeit with some Japan-specific modifications. ACE are relatively low in total energy and their use would require some modification in size, and with respect to tram use it would be necessary to solve small engineering problems and determine which type of charge is explosive material bakes best economic and operational sense for the village. Both measures would require increasing the caliber and accuracy of the current forecasting program as well as unprecedented cooperation with road maintenance crews.