Journal of the Japan Society of Erosion Control Engineering, Vol.60,No.4,2007

Relationship between relative height and angle of elevation from deposited area
to initiated area of snow avalanches

Taro UCHIDA, Nobutomo OSANAI, Hiroshi MATSUDA, Shinichi HONMA, Takunori NOGUCHI and Motoo SAKAI


Abstract

To clarify role of hillslope scale on extension of dangerous area of snow avalanches, we examined relationship between relative height (H) and horizontal ravel distance (L) from initiation area to deposited area of snow avalanches. We analyzed 741 snow avalanches data in literature. We found that angles of elevation from deposited area to top of initiation area were varied from 18 to 40 degrees. When the H is less than 100 m, the angle of elevation of most of snow avalanches is more than 28 degrees. While, the angle of elevation of relatively large snow avalanches (H„500m) is larger than that of small H avalanches. This means that the relative height controls the angle of elevation, suggesting that the hillslope scale is an important factor for estimating dangerous area of snow avalanches.


Key wordsFsnow avalanches, aerial photograph, relative height, angle of elevation
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