2022 Volume 84 Issue 4 Pages 341-358
In the winter of 2020/21, the southern part of Sorachi, Hokkaido, experienced heavy snowfall. Iwamizawa recorded the snow depth of 205 cm which is the second−highest following 208 cm observed in 2011/12. We analyzed the structure of the snow layer and the factors thereof during the heavy snowfall in Iwamizawa, as well as its impact on the local economy and citizens' lives. We compared it with the results of future projections of heavy snowfall. Snow profile observations were conducted twice in the period immediately before snowmelt runoff. Compared to the winter of 2011/12, when snow was mostly lumpy, the snow in winter 2020/21 was affected by high temperatures and rainfall from mid−February onward. Furthermore, the snow texture in the latter was mainly rough with several aquifers and a high sleet content. The reason for the heavy snowfall was that a pattern of streaky clouds over the Japan Sea moved over the Iwamizawa area on many days due to westerly winds. In addition, in late February, meridionally elongated clouds to the west of northern Hokkaido merged with streaky clouds over Ishikari Bay and caused heavy snowfall when they reached the Iwamizawa area. The local economy and citizens' lives were greatly affected by the suspension of public transportation, accidents caused by falling snow, and collapsed houses. The population of Sorachi is aging rapidly, with the elderly accounting for 40 % of the total, and the risk of snow−related accidents is exceptionally high.
