How do you "Read" the Wind?

[NWFlyer 2]

With the recent incident in SA that was related to a dust devil, I thought I'd post/update a list of things I look for in "reading" the wind (that I posted in another thread a while ago). I've got no idea how things looked in Bloemfontein before the jumper got caught in the dust devil - it's very possible that it really did come out of nowhere... sometimes, weird air does. But a lot of times, there's warning signs or things we should keep an eye out for to minimize our chances of getting caught.

Heck, even though I'm the original wind wuss, I got caught near the end of USPA Nationals this year by not paying attention to one of the things on my own list (#3) - I got bit by object turbulence on an off landing. Fortunately I just got a headache and a bit of a whiplash injury.

1) Wind speed. I typically try not to go over 20 MPH, regardless of any other circumstances. Others may have a higher limit, but at some point high winds become an issue even if they're steady.

2) Wind gusts. What's the differential between the high/low winds? More than a few MPH and I'm watching very carefully because that tends to create some weird air.

3) Wind direction part 1. Is the wind coming over obstacles that can create turbulence well into the landing area?

4) Wind direction part 2. Is the wind direction fairly consistent? If it's changing frequently, it can create some weird air and/or put me in a position where I'm setting up to land into a steady wind and end up landing into a steady crosswind or steady downwind.

5) Observations part 1. When I watch other people land, what are their canopies doing? Are they coming in nice and smooth, or are they buffeting? Are cells even collapsing? Are people who are normally smooth landers having hard / weird landings?

6) Observations Part 2. Do I see any evidence of turbulent air, such as dust devils or swirling debris?

7) Other known quantities. Does this dropzone always get weird winds at a certain time of day or a certain time of year? Does the weather forecast say a storm's brewing?

8) Who's sitting down? Last but definitely not least, pay attention to who is jumping and who is sitting down. If most of the people on the jump are working jumpers (tandems & videographers) and guys with under a few hundred jumps, look around for the rest of the folks. Chances are they'll be hanging out in a comfy chair by the landing area, watching other people get "experience." Go hang out with them for a while.

I'm sure others have more to add to this list...

"There is only one basic human right, the right to do as you damn well please. And with it comes the only basic human duty, the duty to take the consequences." -P.J. O'Rourke

[skydivingchad 0]

Sometimes dust devils do come out of nowhere. When I got caught in the one that broke me, it was a no wind day. 100 ft from where I got caught in it the streamer was limp.
Looking back at the conditions once we were able to, it was May, the temps in the morning were still relatively cool (in the 40's) and warming up quickly (it was in the low 70's). It took me out between 12 and 1 pm. That probably caused enough of a air temperature mix to start it going.

Sometimes you're the windshield, sometimes you're the bug.
Pelt Head #3

[Divalent 89]

Ya, dust devils form when there are little or no winds, as otherwise they would be unable to sustain their vertical structure. So they are not something you would expect on a day when there are other wind conditions that are causing you concern.

Wikipedia has a pretty good article on them, and notes the conditions that favor their formation http://en.wikipedia.org/wiki/Dust_devil

From that article:

Certain conditions increase the likelihood of dust devil formation.

- Flat barren terrain, desert or tarmac: Flat conditions increase the likelihood of the hot-air "fuel" being a near constant. Dusty or sandy conditions will cause particles to become caught up in the vortex, making the dust devil easily visible.

- Clear skies or lightly cloudy conditions: The surface needs to absorb significant amounts of solar energy to heat the air near the surface and create ideal dust devil conditions.

- Light or no wind and cool atmospheric temperature: The underlying factor for sustainability of a dust devil is the extreme difference in temperature between the near-surface air and the atmosphere. Windy conditions will destabilize the spinning effect (like a Tornado) of a dust devil."

[Remster 24]

Quote

Sometimes dust devils do come out of nowhere. When I got caught in the one that broke me, it was a no wind day

Most dust-devil days at Eloy are very low wind to no wind days.

Remster

[mattjw916 2]

Another helpful suggestion I received recently from someone with much more time in sport than me was to take a look at the flags or other indicators in the landing area and ask yourself if they are all blowing the same direction. If not, that's a good indication an invisible dust devil or something else you don't want to fly through is in the area that you may not be able to see from your angle.

NSCR-2376, SCR-15080

[skydivingchad 0]

The bad part of my encounter was the fact that I couldn't see it at all. I formed on the grass and stayed on the grass in PA. I have been to Eloy and have seen a few there. For the most part easy to spot them.

Sometimes you're the windshield, sometimes you're the bug.
Pelt Head #3

[almeister112 0]

Dust devils forming/moving over grass is definitely a big worry. I always tell visitors at Eloy to land out in the desert if you see dust devils anywhere near you as you come in to land. You're much more likely to be able to see and avoid one if you're over dirt than over grass.

[NWFlyer 2]

Bumping in light of the recent Eloy injury that may have had to do with wind conditions.

"There is only one basic human right, the right to do as you damn well please. And with it comes the only basic human duty, the duty to take the consequences." -P.J. O'Rourke

[chuteless 1]

Its not hard to read the winds. Having been skydiving since 1962, and taking a spell off to fly hot air balloons for Corporations, one gets to understand wind velocity, and things like dust devils, and gusts. It takes being observant, and making mental notes about the wind conditions that are around you and what the weatherman tells you on TV. Watch for things the wind has an effect on, like small bits of paper blowing across the grass, or as in hot air ballooning, we would inflate a small 1o inch balloon and send it aloft. You can see the wind at different elevations, and the way the wind indicator changes direction, and you watch how it blows the small balloon, and remember what you saw when you are preparing for your landing. Most of all, be prepared when you land. Expect the unexpected, and don't be taken by surprise. I have don that myself, and it hurts when bones break. It is all about being observant and using your memory to apply it to your skill in jumping. Stay safe. Bill Cole D-41

[billvon 2,396]

If anyone is interested in a detailed analysis of what happens to wind near the ground, "Understanding the Sky" by Dennis Pagen is an excellent read.