"Mau taught me to call clouds that look like this "the road to the wind." Imagine at the far horizon there is a factory producing the clouds and, like smoke from a haystack, they follow the wind. This road indicates the wind is coming from the horizon. and because the road is straight, the wind is steady. If you see the road curve--it means that the wind direction will change and the way it curves will tell you the new direction. It is interesting to me that meteorologists call this kind of phenomenon "cloud streets', pretty close to Mau's term "Road of the Wind."