MNTornadoGuy
Member
It's too hard to tell if they were debarked due to the bad contrastThat first photograph...wow those trees look white, were they debarked? If so that's some of the most violent tree damage I've seen outside North America.
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It's too hard to tell if they were debarked due to the bad contrastThat first photograph...wow those trees look white, were they debarked? If so that's some of the most violent tree damage I've seen outside North America.
Interesting, I always thought wedge tornadoes had multivortex structures, I learned something new here.It depends on the swirl ratio, which is basically the relationship between the velocity of the air flowing into the tornado's core and the strength of the updraft. That, in turn, can vary depending on a huge range of factors, many of which aren't necessarily directly related to the actual intensity of the tornado. Even things like debris loading and surface roughness (rugged/forested vs. open field vs. populated area, etc.) have a major impact.
Which I guess is a long-winded way of saying that there aren't really any hard-and-fast rules - pretty much any kind of tornado can theoretically have any kind of internal structure. Just as an example, there doesn't seem to have been any evidence of multiple vortices through most of Bridge Creek-Moore's path.
There are a bunch of really fascinating studies on this and how it influences tornado intensity and whatnot. I'll try to find some of them again later.
Broadly speaking, I would guess that the most violent tornadoes are probably more likely to be multivortex just because of the way swirl ratio works. Very much generalizing here, but if you think about the airflow in a tornado, air is drawn into/around the central low-pressure area and then has to "turn the corner" and be lifted upward. The region where that happens, appropriately enough, is called the corner flow region. That's basically what we think of as "the core," where the most extreme winds occur.Interesting, I always thought wedge tornadoes had multivortex structures, I learned something new here.
Here's a strange question; what do you think the maximum wind speeds were in the main funnel of Bridge Creek-Moore (not the core, the visible wedge) or in any violent wedge tornado? I know the cores and subvortices pack the 250+ mph winds, I'm just wondering if there's a limit to the visible condensation funnel's wind speeds. Not sure how else to phrase that.
I feel that it should be generally accepted that all tornadoes have a multiple-vortex structure. I mean, multiple vortices have been seen in dust devils.Broadly speaking, I would guess that the most violent tornadoes are probably more likely to be multivortex just because of the way swirl ratio works. Very much generalizing here, but if you think about the airflow in a tornado, air is drawn into/around the central low-pressure area and then has to "turn the corner" and be lifted upward. The region where that happens, appropriately enough, is called the corner flow region. That's basically what we think of as "the core," where the most extreme winds occur.
Anyway, the more momentum that air coming into the corner flow region has, the harder it is to lift it upward and the higher the swirl ratio. At a certain point, the momentum is such that the flow breaks down and forms into multiple smaller vortices. Since momentum = mass * velocity, you can see how a tornado with higher horizontal (more specifically tangential) velocities might be more likely to break down into multiple vortices.
Again, I'm simplifying and glossing over a ton of important stuff (updraft strength, debris loading, surface roughness, etc), but that's the general idea as I understand it.
As to your question, I'm not quite sure how to answer it. The condensation funnel itself is just a function of the local pressure deficit and humidity of the air. The wind field in a tornado is really complex and can change pretty rapidly, which you can sort of see in the radically different damage gradients/patterns. And then you can sometimes get particularly intense inflow jets and weird things like the "inflow vortices" that Greg Forbes described w/several of the 5/31/85 tornadoes, etc. They occur well outside of the core (and often outside of the funnel altogether) but can still produce pretty violent winds.
Did any of the Canadian tornadoes from the outbreak produce very impressive damage?So, since my article obviously won't be ready for today's anniversary, I wanted to at least share something. This is simply the most remarkable series of tornado photos I've ever seen, and I'm not sure it's even close. It's not clear exactly who took them, but they were taken from near the intersection of Broadway & Spearman avenues in Wheatland, looking to the south and southeast. This would've been almost exactly half a mile from the core of the tornado (this is the full width of the path, remember - the core is much narrower):
Anyway, the first photo here is taken when the tornado is roughly near the river.
By the second photo, you can already see it striking Yourga Trucking. I believe the huge piece of debris here is the roof, most of which was ripped off in one piece, crumpled up and tossed over a quarter-mile into someone's yard.
I think it's probably tearing up Wheatland Tube here, which is right next door.
In the next few photos, it's likely demolishing Sawhill Tubular and a number of homes scattered around it. The third photo especially gives you a better view of just how small the core is relative to the entire funnel/circulation.
Though the damage throughout this area is exceptionally intense, arguably the most violent damage along the entire path occurs as the tornado crosses the railroad tracks, growing a bit larger as it utterly obliterates a number of homes, businesses and industrial buildings.
Basically the entire funnel swarms with debris as it finally speeds away across an unpopulated area.
Barrie, of course, but I was surprised to find that Grand Valley produced some isolated instances of pretty high-end damage as well. Despite its very long track, most of what you normally see from that tornado comes from Grand Valley itself, and that wasn't where it was most intense.Did any of the Canadian tornadoes from the outbreak produce very impressive damage?
This tornado threw a number of vehicles significant distances, especially between Greentown and Swayzee. This one was thrown a couple hundred yards.Damage and photos from the Kokomo-Greentown tornado.
Greentown was probably an F5This tornado threw a number of vehicles significant distances, especially between Greentown and Swayzee. This one was thrown a couple hundred yards.
The first one here was apparently thrown around half a mile (I'll never not be amused by how incongruous this photo is).
And a car parked in one of the driveways in the famous Greentown aerial shot was also thrown > 1/2 mile.
A few vehicles were apparently "crushed" around this area as well, although I don't have any specifics.
Sort of gets overlooked, I think, but it was a very violent tornado. The damage around the outskirts of Marion was nearly as intense as Greentown in some places.
I haven't done any research on it, but here's Grazulis' entry:While I know some basic details about the 8/10/1924 Thurman, CO tornado in that a farmhouse was leveled or swept away killing 10 of the 18 people inside and that the tornado was an F4 to marginal F5 I would like more details.
Anyone have damage pics, and what was the tornado rated by Fujita and Grazulis?
Thank you!I haven't done any research on it, but here's Grazulis' entry:
CO AUG 10, 1924 1345 10k 8inj 200y 20m F4
WASHINGTON / KIT CARSON - Moved ESE from 4m ENE of Thurman, destroying one farm. Four families had gathered for Mennonite services at the close of harvesting. After the meal, five funnel clouds were spotted in the distance, and two appeared to touch down. The men left on what might have been a rescue mission. No damage was found. They returned in time to see their own home being swept away by another tornado, killing nine children, one woman, and seriously injuring the other occupants.
While I know some basic details about the 8/10/1924 Thurman, CO tornado in that a farmhouse was leveled or swept away killing 10 of the 18 people inside and that the tornado was an F4 to marginal F5 I would like more details.
Anyone have damage pics, and what was the tornado rated by Fujita and Grazulis?
Some sources also cite those as damage pictures from the May 25, 1932 Phillips County, KS tornado.
It's from Grazulis's site and he lists it as from the Thurman tornadoSome sources also cite those as damage pictures from the May 25, 1932 Phillips County, KS tornado.