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Total destruction


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This is my first post. I'm a 68 year old grandfather. I'm the president of PCS VacDry. I had one semester of meteorology in college. I have taken this to NOAA and this is the third forum. Let me begin.

Something unexplained happened in my front yard on November 11,  It was a sunny and crisp fall day. I don't know what the temperature was. There was little or no wind. My wife went to do an hour or so of shopping right after lunch and all was well. This is a picture of our front yard and a canopy that we had. We have had canopies for around 30 years. I have always had them tied to trees, staked to the ground and I have always had  the ridge tied to a heavy picnic table. 

 

 

981165949_yard4.jpg.e75b7828eb7099048f745c0a61b945b2 reduced.jpg

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That test worked. Here is a satellite picture. We are at 41.2020'N,77.2644'W I was in my office at the left. The arrow points to the canopy.

The next picture shows us with friends so you can get an idea of the size.

The third picture shows how the canopy would have looked to my wife when she went down the driveway.

As you saw in the satellite image, Pine Creek runs through my front yard. There is a ramp down to the creek that is left of my Miata in the fourth picture.

 

 

 

 

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ramp.thumb.jpg.c9afc608ae87341fd464f06a0d24f009 reduced.jpg

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This is where things start to get weird. The canopy was totally destroyed. The picnic table is 8' long and pressure treated. It landed upside down. The canopy was shifted toward the left. It was rotated at least 180 degrees. You can see from the previous pictures and these that the solar panel that had been on the left ended up on the right.

 

Ran into a problem. I seemed to have reached the limit on uploaded pictures. I'll see if anything can be done because some of the pictures are essential. It will be a PITA if I have to go back and resize all of them.

 

And we didn't even get to the weird part yet.

 

306552567_1.destruction1.thumb.jpg.2f260bb4a01e0b237acd37fdf45e28a5 reduced.jpg

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2 hours ago, DeltaT13 said:

I'll be interested to see more pics.  If we can rule out vandalism I would consider something like a dust devil.  They can causes pretty intense and extremely localized damage.  

Only real dust devil I've seen was when I worked at a NNJ lake resort back in the '60s.  It had been a calm, hot, dry day until mid-afternoon when a sudden north wind turned the small (30-40 acre) lake into whitecaps.  We heard some crashing at the south end of the lodge, which faced west toward the lake.  The spinner moved behind the lodge, into the wind, and NW-ly across the beach, tossing chaise lounge cushions into treetops and flipping one of the heavy wooden lounges end over end, also flipping the 14' aluminum boat upside down, narrowly missing a co-worker.  It picked up one of those 30" tall metal "can" ashtrays and carried it 1/4 mile across the lake, then dissipated against the steep slope on the far shore.  Was weird watching that can going round and round while 50' above the water.  I'd guess winds were well over 50 in the spinner's 30-40' diameter.  I could easily see a similar critter doing the damage shown in the above pics.

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Here is a very off the wall idea, Do helicopters every fly around that area?  I have power lines behind my house that are frequently inspected by choppers.  The prop wash from them flipped my canoe and tossed it across my yard once.  Other than that, there was no other damage.  

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53 minutes ago, DeltaT13 said:

Here is a very off the wall idea, Do helicopters every fly around that area?  I have power lines behind my house that are frequently inspected by choppers.  The prop wash from them flipped my canoe and tossed it across my yard once.  Other than that, there was no other damage.  

That is something that I hadn't considered. Occasionally, the state or somebody flies low over the creek spraying for black flies.

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Let's start looking at the weird stuff. 

The first picture shows one of the base feet from the bottom of a pole. It was very near where it started. That makes me think that the canopy went straight up.

There were many broken ropes so it went upward with a lot of force.

The third picture shows stuff that was under the canopy and was largely undisturbed.

The fourth picture shows chairs knocked over but in the background is a big Kevlar canoe. If you aren't familiar, Kevlar canoes are very light weight. There are no ropes holding it down. How can this be?

straight up.jpg

broken ropes.jpg

stuff under canopy.jpg

boats and chairs.jpg

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This is copied from another forum. Ted thought that some kind of whirlwind developed over the warm water of Pine Creek and came up the ramp. Bob is a meteorologist who says that can't be true. To this day, he thinks that vandals did it.

 
Ted
The term "dust devil" isn't much used in the eastern US because it's something that happens mainly on open arid land with intense solar exposure. Microburst is closer but incomplete because it refers specifically to a small focused downdraft. I don't know if there's a term other than the broad "waterspout" for a mini tornado that follows streams but I've seen them. They wobble and sometimes flick up onto the banks briefly before dissipating or returning to water. And little twisters (dust devils where it isn't very dusty) happen. In the 1970s I was working at a manufactured housing plant in North Carolina when one touched the holding yard. A doublewide half sitting on tires & hitch was tipped over while a big unbound stack of 2x4s right beside it was undisturbed
 
Bob is the meteorologist.
 
Bob
I don't know what you saw, but your description doesn't match the the atmospheric physics that would be at work here.
 
Yes, you need a thermal differential to form a devil, but Rocky mountain stream temperature would be very cold before a "sharp cold front", say 40F. Even if a cold front was 20F, and you had a 20 degree differential, and it persisted long enough to possibly form a vertical column of air: the horizontal wind speed associated with the sharp cold front would be very high and too strong to enable the vertical updraft due to a thermal differential to form/maintain itself. Plus, the speed of stream water would also dampen any vertical updraft over the stream. It would carry the base of the vertical column of rising air, down stream, stretching it out of shape to its death.
 
But let's say in this case, a creek-devil did form. That the temperature differential between water and air was high enough to create an updraft. Plus, the motion of the water was weak enough to not stretch the column of air. Plus the motion of the air was strong enough to move the creek-devil on shore to the campground canopy/picnic table. This creek-devil (surface based and not dropping down from a cloud on this sunny day) would then need to be large enough to destroy the canopy AND lift/flip the large heavy table yet not displace the the items under the canopy. Recall, OP said they were still in place. Being the lightest items in the destruction zone they should have been thrown to the far corners of the earth had wind (horizontal or rotational) been at work here. (Google Beaufort wind scale for empirical effects due to wind speed).
 
Two things make this operational/research meteorologist think this was not a wind driven event:
No displacement of items under the canopy despite canopy destruction and table movement.
No indication of weather according to OP to cause a wind event: sunny, not windy, not stormy.
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The cover is 3-layer polyethylene with rip-stop embedded. It was ripped the entire 20' right along the ridge of the canopy.

The poles were 1.375" steel. I used the white tape to hold them together while I assembled the frame. Those with tape on one end would have been vertical and the ones with tape on both ends would have been "rafters". In the second picture of my second post, you can see where the poles were used.

Look at those poles and tell me how an animal or a vandal could do that. I don't think there is any possibility of an animal or a vandal and that's why I went to NOAA and I'm now here.

Anybody have any ideas?

bent 1.jpg

bent 4.jpg

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  • 2 weeks later...

Doesn't anybody have any possible scenario no matter how unlikely it sounds? Hundreds of people have been shown the pictures and have read the description and the most suggestions came from a Miata forum. I really hoped to hear something, anything, from a weather forum of this size.

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So I'm not a meteorologist but an Engineer by trade. A lot of my time is devoted to solving odd problems and in my experience the simplest answer is usually the most likely root cause.

In your case I think the damage was cause by a straight line gust of wind while one side of the tent was open. Three sided structures are against code in a lot of areas because of how prone they are to wind damage. It wouldn't take much for your tent to be picked up by the wind if one side was open and basically turned into a large sail, taking the picnic table with it and causing the destruction you see.

as far as the canoes go I'm not surprised they stayed put. Even though they are light there's nothing there to really generate lift.

Just my two cents.

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On ‎4‎/‎6‎/‎2019 at 11:38 PM, Den Socling said:

Doesn't anybody have any possible scenario no matter how unlikely it sounds? Hundreds of people have been shown the pictures and have read the description and the most suggestions came from a Miata forum. I really hoped to hear something, anything, from a weather forum of this size.

Going back to the experience I described above, and considering the comments from Met Bob, I'd still nominate a dust devil, albeit dustless in that locale.  Some added info to what's shown in my earlier post:  In an otherwise HHH summer (1966 reigned as NYC's hottest met summer until dethroned in 2010), the "DD" day was hot and dry.  When the gust front, or whatever, arrived, there was full sun - before, during, and after, with little/no change from the 90+ temp.  There were several other chaise lounges on the beach, some within 5 yards of the one tossed down the beach, and those others didn't even have the cushions blown off, evidence that the event was truly "micro."  As the spinner crossed the lake, the water beneath was churned while for most of the passage, but was unaffected as the event neared the far shore.  A similar phenomenon in your event could cause the canopy damage (and I agree with Luke that the canopy's flight probably upended the table) while leaving light objects on the ground largely unaffected.  However, w/o eyewitnesses we're all just guessing.

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I've been traveling and haven't checked in for awhile. A "dust devil" is indicated. I just wish I understood the circumstances that made this extremely unusual event occur. I have had canopies down there for decades with no problem. This weekend I'll be setting up a replacement. I sure hope that whatever it was doesn't happen again.

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My wife and I moved this table today to make room for new stone and the new canopy. It took both of us on one end to move it a foot or two sideways. Then we went to the other end and moved it a bit. Back and forth that way to move it a couple feet sideways. What could have lifted this heavy SOB and dropped it upside down? It's just crazy!

 

heavy table.jpg

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  • 3 weeks later...

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