It is also pointed out that, in areas where kosa can originate that are surrounded by mountain ranges, for example, the Takla Makan Desert, a strong wind called yamatanikaze (mountain-valley wind) blows at the same time every day, making dust fly up.
周囲を山脈に囲まれたタクラマカン砂漠などの高低差が大きい発生地では、ほぼ毎日同じ時間帯に山谷風と呼ばれる強風が吹き、これが砂塵を舞い上げているとの指摘もある。