Re: Updrafts, & Downdrafts
Bigwheels,
For what it’s worth, I think Monte is spot on. SWAGing the vertical wind especially over open terrain like you are shooting takes some getting used to... And then, it is never 100%. Keeping as accurate data as you can for your weapon system will be your best bet over time.
The diagram in Sean’s article is ok but it doesn't paint the complete picture. Approx every 10 feet of elevation from ground level up the wind changes speed. (Of course ground level is relative to your position and the position of the target in which you intend to engage.) This is due to ground temp, air temp, hi and low pressures, micro terrain and other factors that can go on and on. Reading the terrain and determining how the wind is moving over the terrain will give you a leg up for the most part. The best way to describe it is how water moves over rocks in a stream. If you think about how water moves over rocks in a stream you will have a good idea how the wind works while it is moving over and through draws, fingers and valleys. But, you must first establish the general wind direction.
Reading the conditions that Sean described in his article i.e. leaves, grass and the like is a good indicator but are not a constant. Contrary to popular belief grass, leaves and other biological indicators are subject to collecting moisture. Therefore, a dry leaf will act differently from a wet or green leaf. Temperature plays a part in that as well. Colder temps will lock in moisture and will not allow the plant to act as it would in warmer temps. I’m sure you can see where I’m going with this. Again, accurate data will get you through things like this.
Without writing a book on it here, your best bet again, is to keep accurate data for the conditions that you shoot in. The more problems that your terrain dictates for your firing solution, the more finite you need to get in recording your data. PDA's and other electronic gadgets are great for starting data but there are none out there with the technology needed to give you accurate data for the situations you describe. I know, I won't make many fans with that comment but it is what it is.
I surely don’t have all the answers but I can’t emphasize enough about keeping accurate data for each weapon. Maybe I’ll see you at the Steel Challenge in Kettle, Falls. If so, we can talk about it further.