Introduction of a small-scale avalanche observation site in a warm region, Hijiori avalanche test site in Ohkura Village, Yamagata Prefecture（温暖地域における小規模雪崩観測するサイト―山形県大蔵村の肘折テストサイト―の紹介）

抄録

The Hijiori avalanche test site, Ohkura Village, Yamagata Prefecture, Japan, was established during the winter of 2010/11 to observe small-scale avalanches in warmer regions. The site has been monitored by meteorological observation, and slope has been monitored using a web camera and UAV aerial photography since the winter of 2018/19. The regionʼs warm climate makes it prone to glide avalanches, and webcam monitoring has confirmed 56 avalanches in 13 winters, of which 97 % are glide avalanches. In winter, the wind direction is predominantly west-northwest or northwest. It is almost directly orthogonal to the ridge of the target slope, which makes it easy for cornices to develop. Simulations were also conducted using photographic and UAV data, which are being verified. To use the Hijiori avalanche test site more effectively in the future, we will continue to publish information that contributes to avalanche research by organizing the accumulated data.