抄録
When Yamase which causes cold damages in the part of the east coast in Aomori prefecture blows, the helm cloud on the top of the Hakkoda mountains is observed from the Tugaru region.
Judging from weather maps, it can be said that the appearance of the cloud is clear when the pressure gradient from east to west is great. It is also clear from weather data as well as aerograms that the cloud exists when the air mass of low potential temperature accompanied by cold sea fog from Okhotsk sea flows over the Hakkoda mountains.
