noun
banner clouds in layers
A specific cloud formation resembling layered banners; a technical term in meteorology.
山の上空に八重旗雲が現れると、天気が崩れる前兆と言われる。
When banner clouds in layers appear above the mountain, it is said to be a sign of worsening weather.
Compound of 八重 (yae, 'multilayered') + 旗 (hata, 'flag/banner') + 雲 (kumo, 'cloud'), describing clouds that look like layered banners.