This last weekend I was killing some rocks across a canyon and had a wind situation I havn't dealt with before so I wanted to share it. I will start by saying that I shoot a lot in BIG canyon country (central ID), so I am use to shifty winds, updrafts and down drafts. Usually updrafts and downdrafts are expected with the diurnal winds or if the slope lines up with your prevailing wind. Well I set up to shoot across a canyon that was running West to East ( East being down slope), at the head of that canyon is a major ridge running North to South. I had a full value wind coming from the west (coming over that major ridge running N to S) I adjusted for a full value 10 mph wind and adjusted my dope according to the Kestrel
and ipad, which have been spot on out to 1700 yds. Broke the shot and watched the shot hit 1 1/2 moa low and 1/2 to the R. I wasn't surprised by the windage being off but the elevation got my attention. readjusted accordingly and broke the second shot. Wind was good and but still 1/2 low. Adjusted accordingly and hit the mark. repeated and hit the mark, realigned on the next pile of rocks at 1625 and repeated the process. This rock required 3 1/2 moa extra elevation to anchor, plus the appropriate wind.
My conclusion, as wind travels over ridges, it creates burbles on the backside of those ridges and down air is the result of those burbles. To back that statement, I was at the same canyon the next day, no wind situation, dialed in my original dope and cold bored the 10x on my rock. Repeated that at the 1625 rock. Something to think about in canyon country.