Need help with damage photos

[Marko Korosec]

Hello all,

I would need some help from experts to decide if the damage was made by tornado or by downburst.

We had a severe weather day on Thursday, with a possible tornado at one location. Here is a news report:

In municipality of Kidricevo strong wind caused a lot of damage, roofs were blown off, hundreds of trees down. There was also a lot of houses badly damages, chimneys, walls...

A friend of mine was there on that area and took these pictures (© thorr, Slovenia):

This is a view to the area from south:



Photos of trees down, rural fields damage:



















Some trees were also blown in the opposite direction from the others:

http://img192.imageshack.us/img192/5137/dsc042185ot.jpg

http://img192.imageshack.us/img192/7327/dsc042171ib.jpg

Destruction deep in the forest:

http://img192.imageshack.us/img192/9954/dsc042335xx.jpg

http://img192.imageshack.us/img192/8559/dsc042357vm.jpg

Narrow zone where almost all was destroyed:

http://img192.imageshack.us/img192/720/dsc042369zr.jpg

http://img270.imageshack.us/img270/9889/dsc042602fo.jpg

Very sharp boundary where lot of damage trees is down, but behind them they are not even touched:

http://img270.imageshack.us/img270/7913/dsc042559bm.jpg

More photos of the damage:

http://img192.imageshack.us/img192/3892/dsc042395xc.jpg

http://img249.imageshack.us/img249/8532/dsc042405mn.jpg

http://img192.imageshack.us/img192/5184/dsc042438rx.jpg

http://img270.imageshack.us/img270/113/dsc042467dg.jpg

http://img270.imageshack.us/img270/5278/dsc042489kq.jpg

http://img249.imageshack.us/img249/5219/dsc042505pk.jpg

http://img192.imageshack.us/img192/5970/dsc042546ku.jpg

http://img249.imageshack.us/img249/9493/dsc042561dm.jpg

http://img270.imageshack.us/img270/6350/dsc042576qc.jpg

http://img270.imageshack.us/img270/5291/dsc042591cj.jpg

http://img249.imageshack.us/img249/1254/dsc042616qj.jpg

There was a lot of damage in the closest village Apace <2000m away from the location above.

http://img270.imageshack.us/img270/7493/dsc042634ev.jpg

Here is a link from our TV news report, it is in Slovenian but you would see the video:

http://24ur.com/naslovnica/novice/slovenij...77_16121221.php

Here are some things which he reported besides the pics:
1) most of the trees down is in the same direction (towards south)
2) its hard to say the path of destruction, small areas of trees are scaterred in all directions
3) if you look at the whole area, there is a path with sharp edges of almost total destruction at one area of the forest
4) some of the trees are in different directions
5) area of destruction is just 500-1000m wide

Thanks for any kind of help. If you guys need some more informations, just ask! I have radar and satellite images, including the sounding diagram which my help.

I personally am more into downburst damage, especially after sounding diagram.

Best regards,
Marko

 

[Karen Politte]

Hello all,

I would need some help from experts to decide if the damage was made by tornado or by downburst.

If you guys need some more informations, just ask! I have radar and satellite images, including the sounding diagram which my help.

Best regards,
Marko
[/b]

Hi Marko!

Please post this sounding/radar information, Marko! It's very hard to say from the photos posted - as there are suggestions for both tornado and downburst.

I hope others chime in and give you some help, too. I'd like to see the radar info etc. before guessing with this case.

Regards,

Karen

 

[Angie Norris]

Hi Marko!
If there are any aerial views, those would be extremely helpful as well. Was a path length determined? Did any of the residents see a funnel?
My first impression, just from the tree damage, would be microburst, which would be supported by the width of the damage area.

 

[Marko Korosec]

Thanks for all responses!

It happened around 00:40 UTC on June 30th. so it was 02:40am local time, overnight. There is noone that could see this since all were sleeping. Here are some more details about this event...

Sounding diagram for the closest station Zagreb at 00z:



Is it just me or there is a pretty good downburst potential?

Radar capture at the time of event (location is marked with blue dot)...sorry about poor resolution, Tim would know what I am talking about; restricted weather data/images from European weather offices, so public can get just this one, even there is much better one available:

Here is a 3.5h radar animation:



Satellite image:

lightning activity: http://blitzortung.org/cgi-bin/archive.cgi...r=4&min=0&sec=0

An approximate damage area:

An interesting thing here is the orientation of the most damaged area (small area inside red area), which shows NW-SE orientation, but on the sounding diagram you can see south-westerly winds with cells going into ENE direction.

Hopefully I will get some aerial photos tomorrow during day and will post them here as well. I am probably going there tomorrow to look at the situation with my own eyes.

Thanks again for your time! This is pretty rare thing in our country, we rarely get something like this, maybe once in 5-10 years!

Regards,
Marko

 

[Stuart Robinson]

Hello Marko,

I have taken the time to study all the images and based on my own experiences of tornado touch down investigations (over the UK) the images at first do suggest a tornado has occurred – but I would need to have conclusive proof before I confirmed it. One thing I did not see from any of the images was evidence of lofted debris – did you spot any during your investigation.

In wooded area these are actually easer to spot after a week or so has gone by. Look for snapped off branches with brown leaves up high in the surrounding trees. These are hard to spot while the leaves are still green.

Still based on the balance of the evidence before me – the evidence of track length suggests a tornado over a microburst



One last point (and off topic!) – why is the telephone pole a bent pole ?? – top left of image.
http://img270.imageshack.us/img270/7493/dsc042634ev.jpg

 

[Jeff Snyder]

I'd take that sounding with a big grain of salt, since I can't imagine it is representative of the environment those storms were in... LCLs are low for a surface parcel, but you wouldn't be able to get surface-based convection given the amount of CINH for a surface parcel. In order to destabilize that sounding, you'd need to increase the low-level temperature or decrease the mid-level temperatures. How far away from the damage was that sounding taken? If the low-levels near the storm were warmer, the LCL was likely higher as well... Tough to say w/o correcting the low-level thermo profile for conditions near the storm. The kinematic profile is nice, however.

Marko, that's certainly a tough case w/o aerial photos. I think the strongest argument may be for straight-line winds, given that you said that most damage (trees, mainly) had the same orientation. The picture of the grass/crops (3rd from the bottom of the pictures that show up) almost looks like a "fan", indicating divergent flow. Tough to know what to make of the fact that some trees are 'laying down' in different directions, though I'd expect there to have been small-scale eddies / vortices created by the intense winds that may cause local differences in 'fall direction'. I guess the biggest piece of evidence would be whether the trees are all down in the same direction as you walk east-west through the damage area. If they are (which it sounds like is the case for the most part), then I'd think microburst. Do you know how fast the storm was moving? If the storm was moving slowly, then I would have guessed that you would have seen trees laying the opposite given surface divergence that characterizes most microbursts. Are the trees mainly laying to the north? What about the trees on the south side of the damage area?

I have no in-field damage assessment experience (I think there are few on this board that do, though), so I am in no way qualified to give any sort of true assessment. My 'best-guess', however, is straight-line wind damage.

 

[Evan Bookbinder]

I think the evidence clearly shows a case of straight line winds.

The sounding shows that there is a stout elevated mixed layer above a steep frontal inversion. The sounding clearly does not support convection based in the boundary layer -- or anywhere close for that matter. Ignoring the blue/red shading for SBCAPE, a forced parcel for deep convection should originate from about 850mb at the top of the inversion, with an impressive amount of CAPE above (owing to a deep elevated mixed layer).

In the radar loop, you can see (even in the very low resolution) generous amounts of ordinary elevated ordinary convection north of the frontal zone, with an apparent supercell along the southern periphery of the convective zone early on. Over time, this apparent supercell continues northeastward, ultimately morphing into a small linear segment at the end of the loop. A nice embedded bow echo segment just NW of your area also develops at the end of the loop as well.

Using the 850mb parcel, you can see that the cloud bearing shear is actually quite impressive for that region. More importantly, note the very high theta-e content (relative to the boundary layer) within the frontal inversion. This, combined with substantial dry mid level air, supports a classic case of unusually high downdraft CAPE (or DCAPE) potential.

Like others have stated, an areal photo of the damage would be great here, but from everything I've seen, the evidence would definitely tend to support a localized downburst associated with this elevated supercell. Was there any hail in the area as well?

The orientation and scale of the damage swath, compared with storm motion, would also tend to suggest that a tornado was not the cause of damage.

Thanks for sharing Marko. This is a wonderful case, and in such a terrible down year for severe weather in the US, it's even more enjoyable to see the origins of severe convection in other parts of the world.

Best wishes,
Evan

 

[Marko Korosec]

One last point (and off topic!) – why is the telephone pole a bent pole ?? – top left of image.
http://img270.imageshack.us/img270/7493/dsc042634ev.jpg [/b]

Because that part of country is pretty poor, but actually we mostly have bent poles for these things.

First of all, I have to apologize about a huge mistake I did in my previous statement. My post was based on report by our national television who said this event happened at 02:40am local time on June 30th, but this was wrong!

Today we decided to look over the situation by ourselves there, we were talking with some local citizens who gave us some more important informations.

The actual event happened at 7:00pm local time on June 29th, which means almost 8h before first thinking. This now put things in different way, because there were some eyewitnesses who said that the cloud base was just few hundred metres above the ground, there was an extremely intense downpour almost with no hail. Noone did not see any rotation, it was just insane wind blowing around.

So here are now new radar and satellite images, including additional sounding diagrams.

Two radar images at 7pm local time (17z) when the event happened over that location (blue dot on the first scan is event location):

Radar animation (notice severe intense cells/supercells south of Slovenia over north-central Balkans and notice that there was another cell about one hour before this one around 17:00 UTC, but damage was not caused by that one):



Visible + Infrared satellite image for NW Balkans, event location is marked with blue dot, yellow dots are locations for soundings.:

June 29th 12z sounding diagram for Udine, Italy about 150km west of event location:


June 29th 12z sounding diagram for Zagreb, Croatia about 50km south of event location:


June 30th 00z sounding diagram for Zagreb, Croatia about 50km south of event location:


Here are all three raw formats for above soundings: http://www.weather-photos.net/images/sounding-raw.rar

Here is a link to European Storm Forecast Experiment (ESTOFEX) forecast for that day: http://estofex.org/cgi-bin/polygon/showfor...ormforecast.xml

These are additional 8 photos I took today:

http://www.weather-photos.net/gallery/albu..._07_2006mk1.jpg
http://www.weather-photos.net/gallery/albu..._07_2006mk2.jpg
http://www.weather-photos.net/gallery/albu..._07_2006mk3.jpg
http://www.weather-photos.net/gallery/albu..._07_2006mk4.jpg
http://www.weather-photos.net/gallery/albu..._07_2006mk5.jpg
http://www.weather-photos.net/gallery/albu..._07_2006mk6.jpg
http://www.weather-photos.net/gallery/albu..._07_2006mk7.jpg
http://www.weather-photos.net/gallery/albu..._07_2006mk8.jpg

And some pretty bad aerial photos, but we're planning to give it another try in few days:

http://img204.imageshack.us/img204/8084/pic02153vf.jpg
http://img204.imageshack.us/img204/2886/pic02202lr.jpg
http://img204.imageshack.us/img204/4395/pic02185cm.jpg
http://img204.imageshack.us/img204/2328/pic02174hk.jpg
http://img54.imageshack.us/img54/1631/pic02169tu.jpg
http://img204.imageshack.us/img204/7997/pic02144gq.jpg

Thanks again for all your responses and analyses, guys. I really appreciate your help!

Best regards,
Marko

 

[Scott Olson]

Marko, it appears to me to be straight-line wind damage. The radar loop you posted appears to show a bow echo most noticeable during the 1640-1650 timeframe. Seeing the trees broken like a row in the same direction, even with some distance in between. As well as general unidirectional (and spotting) damage from the aerial photos leads me to this conclusion.

Some of the vegetation photos & the direction of damage/swath seems a bit suspect though.