Journal of the Japanese Society of Snow and Ice

Influence of different surface soils on snow-water content and snow type of the snow cover

Hiroshi GOTO, Katsuhiro KIKUCHI, Masahiro KAJIKAWA

2012 Volume 74 Issue 2 Pages 145-158
Published: 2012
Released on J-STAGE: September 03, 2022

DOIhttps://doi.org/10.5331/seppyo.74.2_145

JOURNAL OPEN ACCESS

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This study deals with the variation in volumetric snow-water content and snow type on four different ground surfaces : sand surface, lawn, Akita cedar woods and open field of grassland. During the melting period, the snow-water content of the granular snow layer adjoining the sand surface did not increase, and the total water equivalent of snow on the sand surface was smaller than that on the neighboring lawn, although the snow depth was same in both cases. These characteristics mainly result from the differences in the wet density depending on the vertical distribution of snow-water content and snow type. Water permeability and water retention of the four different surface soils were examined. The saturated hydraulic conductivity of the sand surface was larger than that of the lawn, while the water retention of the former surface was smaller than that of the latter surface. These results suggest that the physical characteristics of the surface soils have significant influence on the snow-water content and snow type of the snow cover.

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Avalanches induced by North Nagano Prefecture earthquake on 12 March 2011

Isao KAMIISHI, Hiroki MOTOYOSHI, Masaaki ISHIZAKA, Takeshi SATO

2012 Volume 74 Issue 2 Pages 159-169
Published: 2012
Released on J-STAGE: September 03, 2022

DOIhttps://doi.org/10.5331/seppyo.74.2_159

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The North Nagano prefecture Earthquake（ Mg 6.7 ） on 12 March 2011 induced surface-snow avalanches, full-depth avalanches, collapse of the block-like snowpack and cracks on the surface of the snowpack over wide areas, where the seismic intensity was 6 or more. Especially, within the area, failure surfaces of the snow avalanche were stepped and irregular. The avalanches filled roads at many locations, some of which occurred at slopes even though avalanche supporting structures had been deployed. Earthquake-induced avalanches of snow mixed with rock and sand flew long distances due to high fluidity. According to the snowpack and weather conditions, the likelihood of avalanche at the time of the earthquake was estimated to be low. We calculated the stability index of the snowpack by using an equation that incorporates the earthquake acceleration. The result shows that the index of the sliding surface for a surface-snow avalanche, consisting of wet melt forms snow, was estimated to be 1.5 or less which supports the possibility of earthquake-induced avalanche. Further research is needed to understand the snowpack collapse mechanism caused by an earthquake.

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Comments on “Supplementary note on curl mechanism resulting from left-right frictional asymmetry and frictional force” by K. Tusima

Renji NARUSE

2012 Volume 74 Issue 2 Pages 171-172
Published: 2012
Released on J-STAGE: September 03, 2022

DOIhttps://doi.org/10.5331/seppyo.74.2_171

JOURNAL OPEN ACCESS

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