## Wind Estimation With A Laser

A coupie of years ago, a friend with the Defense Department told me about research under way at Los Alamos National Laboratories to design a laser that could measure wind not just where you were but at a distance as well. Checking the Internet, I found that the Israeli Atomic Energy Commission's Yavne Soreq Research Establishment also is looking into laser wind measurement. This is, however, raw, basic research, and I doubt we'll see a usable device anytime in the next decade.

But that got me to thinking—with so precise a ranging instrument, isn't there some way that a laser can be employed to more accurately calculate wind than the old-fashioned "how it feels on your face" or tossing a cloth to the ground?

Here's what I came up with.

Turn exactly into the wind. Carefully find a point before you —directly into the wind —where you can see some visual effect(s) that a gust of wind has reached that spot. This could be a rustling of leaves, lifting of a string, swaying of a branch—anything that tells you exactly when the wind has reached that spot. Now, laze a point within this area to see where, exactly, is 100 yards or 100 meters. At this exact point is a particular leaf or some tiny item susceptible to wind that you can see being affected.

Working with your spotter, here's how you do it. The split second that you see this item affected by the wind, call, "Now!" and your spotter begins timing. When that same gust of wind reaches you —you feel it on your face or see it affect something beside you —call, "Stop!" He now has an exact time that it took that gust of wind to travel 100 meters or 100 yards to your position. Now, just look at the chart I prepared and you'll know the exact wind speed. Let's say your spotter timed it as 17 seconds, and the spot you'd lazed was 100 yards away. On the chart, that translates to 12 mph.

What's most interesting about my technique is that it also can work anywhere between you and the target, provided there are items out there that are visually affected by the wind and you can determine the wind's angle, as well as a lateral distance of 100 meters or yards.

Here's how this works. Observing a wind at 800 yards, carefully determine how it's laterally crossing your front. Using binoculars or a spotting scope, select two points along this wind line where wind-induced movement can be detected —rustling leaves, etc., just as you did near your own position. Then, very carefully pick two points exactly 100 yards or meters apart for timing the wind's crossing, again calling it out to the spotter.

The first time I tried this, it was a bit confusing to ensure that I was timing a single gust, but with some practice it works better than anything except an electronic wind gauge.