Technical reports
Debris flows caused by heavy rain during the soil-freezing and snow-melting season :
A case of heavy rain at Mt. Meakan in May 2008
2022 Volume 59 Issue 2 Pages 41-49
Details
2022 Volume 59 Issue 2 Pages 41-49
In May 2008, heavy rain caused multiple debris flows on the northwestern slope of Mt. Meakan (1499 m a. s. l.) in eastern Hokkaido. Although the total rainfall was 124 mm, which was once every few years, debris flows occurred for the first time in 50 years. The reasons are rich in the soil moisture at the end of the snowmelt period, and concentration of surface water and shallow subsurface water by prevented rainwater from infiltrating underground in the frozen soil deeper than dozens of cm. A flat-bottomed erosion formed above the upper surface of the frozen soil around the mountaintop, and several m-scale rocks were deposited on the both sides of the valleys on the mountainside.
