Let's pick three (3) features for a start; quantity, quality, direction.
How fast is it blowing??
Is it a steady wind or does it gust and switch.
Where is it coming from, by the clock face method. 12 o'clock, 1 o'clock, 2 o'clock, 3 o'clock, you get the idea.
More in depth.
We each become our own standard in guaging wind speed, I may call a wind 7 mph and another person may call that same wind 10 mph BUT this is not a problem as long as we each are consistent. Consistency is one of the things required for accurate shooting. If you get a wind guage (meter) you can use it to determine wind speed at your current location and you can use it to calibrate your own personal system, feel of the wind on your skin, the sound of the wind in your ears, the look of the grass, leaves, trees etc. as long as you remain... yup!... consistent your system will work fine.
Quality & Direction.
Go outside on a day with a breeze and look across the landscape. What is happening to the world as the wind blows. Observe each and every item you see, tall weeds, leaves, branches, ripples on the water, birds flying or perched, clouds, fog, tumble weeds, critters, smoke, dust. Examine the terrain and try to visualize the wind as a stream of water flowing around and over obstacles, make notes.
Shoot in the wind.... judge the wind PRIOR to shooting, make the wind call and adjust the sight picture or scope, shoot. Record the result and make notes. later take these notes and use them to correct your method, under-calling, over-calling, what's actually needed for the rifle at the given distance and wind speed.
It's not too difficult to "read the wind" and it's something that'll come much faster if it's done pro-active instead or reactive.
Thanks for the article, Dave.!
.. At my 1K pos I'm up on the top of a small mountain that's the first high place after a river basin.. YEP.! Full find with major updrafts..!! Gets me a little lift to go with my deflection.. Hehehe.. [img]images/icons/grin.gif[/img]
... That bunch who planted the big cut-over down at the club was kind enough to mark their territory with a bunch of surveyor's tape all through it.. My, my, my.. What pals..!! I'm loking forward to the next LDC trip this weekend..!!
.. I got one of those little windmeters a while back..What I've learned so far is that it takes a 9mph wind to knock it over if it's not otherwise supported.. I gotta cut me a piece of steel to mount to the bottom of it.. d:^) JiNC
The more I shoot, the more I find myself using clouds, trees, & weeds (or range flags) for general information & trends. Winds often have 'cycles' like waves for surfers. It helps immensely to see what the trends are doing. I guess this figures into Dave's 'Quality' category.
The 'Quantity' comes from watching the trends develop & picking a condition to shoot in if you have the luxury of time. A standing shot on a deer+ sized game animal can wait a few seconds if you are aware of an upcoming wind switch or gust. A spotter is invaluable at these times. It helps to have a high & low bracket of adjustment parameters in mind & release the shot within that window.
'Direction' plays into velocity as shifting winds & channeled wind currents over longer distances play themselves out. A sharp 8MPH 'fishtailing' wind that moves quickly from 8:00 to 4:00 is far tougher than a pretty steady 17MPH wind from a known direction. It has been said that a variance of 2MPH will throw a shot out of the 10 ring on a standard NRA 1,000 yard LR target. That equates to a clean miss or a cripple on deer/elk sized game. A person must know their limits of ability & equipment.
Learning mirage has been the greatest single factor in improving my own (paltry) wind reading ability. The bending, leaning, shimmering waves will show instant shifts in velocity & the dreaded 'boil' when the wind velocity &/or direction transitions to a new speed/lull/momentary zero value. It's also the cause of many, many elevation errors. If your spotter sees you shoot in a boil, you stand a good chance of tossing one high. Knowing the trend, & relying on a spotter when available will help.
Spend 10 minutes looking through a spotting scope the next time you're on range. Watch what the mirage does in relation to the clouds, trees, & weeds. I think you'll see a perspective you may not have seen staring through a scope reticle. The times when I was really on my game were the ones when I would continually look at a wind condition through the day at work & simply think in terms of minutes of angle. It can get that fast & that automatic. [img]images/icons/wink.gif[/img]
Mirage is very interesting as a direction and speed indicator, and I've learned quite a bit shooting with those wave patterns (about .1% of what I still need to!). Up here, mirage can be a very good help at LR, even though it takes longer to verify the targets true position if it's really intense, it does allow you to "see" the wind along the LOS before the shot.
Think of it as another language, and you must learn the meaning to the new words you see through the scope. You learn to associate a distinct sight image to a value and it is not that difficult, just how precise you are is what matters, and what I think is the hardest part. This is something that I think one must REALLY dedicate themself to in order to learn it REALLY well
Mirage has many patterns, or "faces" if you will, least that's one way you can "view" it I guess, [img]images/icons/grin.gif[/img] but looking at it that way you'll see there is many different "faces" to recognize, some very different, some with only very subtle differences. Basic mirage charts are a start I think.
Anyway, faces, letters, words, [img]images/icons/rolleyes.gif[/img] whatever you associate what you see with, it's important to learn to distinguish each one and to translate them into wind speed and direction, as accurately as possible, then you've learned much about the mirage language.
Some very general rules of thumb for wind drift corrections are .1 MOA per every 1 MPH wind, or .1 MOA per every 2 MPH wind, 308 win verses 300 Ultra Mag "approximately".
Of course at longer range you will need to be more precise than those general rules, and they may not even apply to your load very well in the first place, much less at all temps and BP. Here it pays to shoot lots, and take lots of notes too! Ballistic programs fill in lots of gaps, but many data points are still needed to correlate your data to the programs predictions...
Now, to figure wind from two or three different directions, and speeds downrange...
My shooting position on my range is on a small hill about 40 feet higher than the marsh below. One day while shooting at 900 yard steel we watched the direction of falling snow. One particular time its direction was very different from that of my ground-level wind flags. Since the bullet's path was quite high above the wind flags, it was better to use the falling snow to predict bullet drift.
In Mexico a few years ago I shot my Coues deer at 666 yards in gently falling rain. It was easy to predict bullet drift using the rain as a wind flag.
Falling snow and rain are sometimes actually better than shooting range wind flags!
Don't forget the term "condition" as it applies to wind. If you are shooting for hours from a hilltop like we frequently do, you have to memorize or simply acquire in your mind what the mirage and other wind indicators are doing. Best is to get an average "condition" in your mind and try to send the shot during that wind speed and direction.
Have to consider what angle the mirage is running, how grass is moving down at the target and midway, wind direction on a wind-string we always hang a few yards in front of our firing position, wind speed on your face and sound intensity through your muffs, natural contours (as Dave says, wind is like water, slows down going uphill and speeds up going downhill), and wind speed from your electric meter. Naturally you also factor in where the previous shots went, if there was any. Dust from those shots is a great indicator of what direction and how fast the wind is moving down range. Then you eat some humble pie and say "Give me four more minutes left, that wasn't quite enough [img]images/icons/frown.gif[/img] "
When the wind starts rolling us up in the shooting mats like tumbleweeds, we call it quits [img]images/icons/grin.gif[/img] Fact is windy, crappy days are the days we should be out practicing, not the calm, blue-bird days.