Hunting & Fishing How terrain affects wind

[Rerun7]

Posted this in fieldcraft too but it really relates to hunting as well.

Does anyone have a good source of info on how terrain (especially hills/valleys) affect wind speed/direction?

This is something I really need to work on as the place I hunt is pretty steep terrain and trying to keep downwind is a challenge.

 

[AIAW]

I treat it somewhat like a fluid. A good interpretation would be colored dye in flowing water. Like an fluid or gas it's going to take the path of least resistance. That may be "around left or right", "up", "down". The consequence is either a changed direction (swirling, deflection, etc.), velocity or void. That can extend out quite a bit away from the obstacle.

For instance, in the image below: if your firing position was from along the road in the south-west corner to 1 o'clock, you'd experience the 8-12 MPH closer in, then experience a 4-8 MPH further out coupled with a slight directional change induced by the mountain.

I don't believe I have seen any official material on the subject really, outside of it being mentioned briefly in some of Litz' books.

 

[HeavyAssault]

I like to study the effects of snow/sand when understanding the effects of wind. Not to mention the effects can be seen when looking at trees, high weeds, grass, etc etc etc. At the beach, the mountains, watching nature can be fun. I bet if you took up a short study of the weather you could gain some serious info.

 

[Rerun7]

Yeah - it’s a bit perplexing to me. I often run into situations where I’m down wind in open areas but move into some of the valleys I hunt and I’m suddenly upwind.

I would have thought wind speed would be greatly effected but the direction shift is not what I thought it would do when it’s that drastic of a change.

I’m assuming it has to do with thermals and terrain features leading into where I’m going.

That diagram above is a good example. You can see places where the wind is moving up the hill but walk further up and it hits you in the face again because it’s moving all around it and up.