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Fig. 11 Bird's-eye view of slope gradient by the eight-neighbourhoods
square grid system near the yukigata, "Hane-uma".
landslides caused huge snow accumulations.In the case
of the negativetype yukigata, "Hane-uma", cliffs andsteep
slopes and full-depth avalanches caused denudation.
In order to confirm the formation mechanism, on-the-
spotinvestigationsandmoredetailedterrainanalysis
should be done by experts. The occurrenceanddisappear-
ance of yukigatas should be observed and the mechanism
of accumulation,melt and reaccumulation byavalanche
and snow drift investigated.
Yukigatas, which had been valuable as the agricultural
calenders in the past, will be useful not only for avalanche
education butforbetterunderstanding of theavalanche
phenomenon. Further, yukigatas are one of the best teach-
ingmaterialsforunderstanding nature andthe connec-
tion of nature and human beings.
ACKNOWLEDGMENTS
I am gratefulto the members of theyukigataresearchgroup,
Hokushinetu Branch of the Japanese Society of Snow and
Ice,who discussedand encouraged thepresentpaper.I
am also grateful to Mis. Junko Iwahashi, the Geographical
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Fig. 12 Domain combining contour lines of more than 35 degrees and
the cliff near "Hane-uma". The slope gradient was calculated by the
four-neighbourhoods square half grid system.
Survey Institute, Ministry of Construction for her consid-
erableguidanceontheDigitalElevationModel.Iam
deeplyindebtedtoSeniorresearcherTakashi Inokuchi,
National Research Institute for Earth Science and Disaster
Prevention for his commentson mapping of landslide to-
pography.
I wish to thank to Mr. Toru Endo, Shiozawa Anti-snow
Testing Station, Railway TechnicalResearch Institute and
Agriculture and Forestry Section,Shiozawa Town Office
for providing the preciousaerial photographs. Also, I wish
to thank Miss Yukiko Itaya for her assistance with making
detailed Digital Elevation Maps.
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