Odd wind patterns - lower layers flowing opposite to upper layer

I was watching some video footage a few days ago and it was showing a couple scenes of large fires, some were forest fires and others were grassland fires. What was odd was that the smoke was rising about 100-500ft and was being blown by the wind in one direction then at the 100-500ft it turned back the opposite direction, making basically a 90 degree turn as the smoke rose. The video footage showed the smoke rising well past 30,000ft and it had continued in the same direction after it made that turn.

I've also seen this same thing with low hanging clouds or fog, but this phenomenon is most easily seen when there is a fire.

So what I'm wondering is how does this lower layer of wind form so close to the ground and it really makes me wonder when I feel the wind blowing if that is really the way the clouds are moving or that is how they are "rolling in".

So it seems that at times there could be a very thin layer of wind at ground level that is flowing the opposite direction of the wind just a few hundred feet above it, which seems very odd and almost impossible had I not seen it for myself. I can't imagine how this would happen and if you look at how fluids flow, it is a very odd behavior unless there is a major difference in density between the two "fluids" (layers). Also it would seem that there would have to be a SEVERLY low pressure on the lower layer, almost like a vacuum, to make the air flow like this and I thought it might have been due to the fire but after seeing this behavior in colder climates (30-50F) with heavy cloud/fog, I don't think it had to do with fire.

Does anyone have an explination for this behavior or seen this themselves? I think I recall similar behavior in the Cali fires last summer where the fire was traveling the opposite direction, into the wind, of the way the smoke was traveling once it rose a few hundred feet - which is why many people thought they were safe, the "prevailing winds" were blowing say east to west at 1000ft and above, so people east of the fire thought they were safe - but at ground level winds were blowing west to east, pushing the fire in the opposite direction that the smoke cover was seen to be blowing from above (satellite/plane video/images) - so many people ended up being trapped in fires b/c how can the fire travel against the wind?

It's almost like there is a hole in the ground that is sucking in air, pulling the lower "fluid layer" into this "vacuum", causing this odd behavior. This type of behavior often would create a tornado at the point of lowest pressure, where the fluid layers converge, but that is never seen - so IDK how to explain any of this.

a reply to: DigginFoTroof

I will give your credits for your observational skills and pondering. I was aware of airlayers and that the upper airlayers like the jetstream can move in completely different direction to ground wind.

But such variation between low layers....I don't know?

Maybe post your question in Arbitrageur's "ask me anything thread"

ask me anything about physics

That guy is beyond smart and will probably explain it easy. On the other hand I'm sure their'll be someone posting the answer here in your thread.

Peace

Fluid dynamics can be quite counterintuitive. Consider atmospheric jet streams: a 200-knot 'river' flowing through relatively calm air? How can this be?

Same thing happens in the ocean. I've been out in the Atlantic on a small boat many times, and as you approach the Gulf Stream, you can actually see the demarcation in the water between the static side and the flowing side. Idle 10' forward and it sweeps you 'downstream'.

That's the macro-level stuff, created by the earth's rotation. On the micro level, air currents are influenced by uneven heating and cooling of the earth's surface, weather fronts, and associated changes in atmospheric pressure caused by temperature and moisture in the air.

More here:

education.seattlepi.com...

Thanks for the replies and those examples of the jetstream and gulfstream are pretty accurate. I've also seen demonstrations of fluid flow in various combustion processes or chemical reaction tanks where it's very important to have a homogeneous mixture and the fluid boundary layers form keeping various sections of the chamber isolated. This all has to do with the flow of the "fluids" in the chambers, their densities/heat and speed at which they are traveling.

The thing that was so odd in the the weather video's that made me take notice was the 90 degree turn the smoke made. If the air is rising at a constant rate and there are two layers flowing in opposite directions, they would have to be flowing at the same speed for there to be a 90 degree turn, if either were flowing faster or slower, it would skew the angle a good bit.

The first time I took notice I thought I was seeing a video rendering error, with the upper portion being rendered in reverse. I thought that had to be the only explanation for such a distinct and exact error. My mind immediately jumped to media manipulation, possibly enhancing the extent/severity of the fire with rendering - thus the mistake. Then I remembered the video's of last year with similar reports, but video's weren't as clear.

Either way, I'll look into it, I don't think it's anything really nefarious, unless it was infact some kind of video manipulation, and that would mean it was done in many situations. I'll look at other fire videos and see if this is more common than I thought.

Air moving in the vicinity of a wildland fire is especially unpredictable and dangerous. Aircraft used in firefighting efforts have crashed because of this.

Generally, warmer air moves up sloping ground, and cooler air moves down sloping ground. The slope creates a chimney effect; even extremely gradual slopes can create severely high winds when fire conditions dictate. And even on flat ground, the area of a large fire can generate a microclimate due the effect the fires and heated ground have on the air that passes over it.

Additionally, geographic features (hills, mountains, bare land, forested areas, water features, etc.) all affect how the air moves past them. A good example is how a mildly breezy day can generate dangerous winds in proximity to tall buildings in city centers. Even if we haven't experienced it, we've seen videos of hapless window washers hanging on for dear life when the electric winches on their scaffolds fail.

As others have said, wind directions at different elevations change a lot. Clouds at different elevations have always moved in different directions or at different speeds. Pilots vary elevations to match the direction of winds to make better time, the information of these speeds is available to them through various communication channels, when I was learning to fly we called the tower to find these wind elevations when we left sometimes. I suppose the Jets would have computers they could access these days.

You can see the different layers of wind on this website: earth.nullschool.net...

Not sure if some are omitted though, either way was surprising to me the first time I found that website!

originally posted by: 09234
You can see the different layers of wind on this website: earth.nullschool.net...

Not sure if some are omitted though, either way was surprising to me the first time I found that website!

Thanks for posting this link. It is mesmerizing.