Have a look at this picture (click to enlarge):
i-ac945bdfe459de7ca08a2d6eceb924f3-leaves_from_the_sky-thumb-500x331-65270.jpg

We had a tornado here a couple of hours ago. It did not come near our house. It was probably an F2 or so in strength, and based on videos and the reported damage path it was about three or four tenths of a mile wide or wider at times, as it moved along a path of about 10 miles or so (maybe 20 by some reports), four of those miles being as a strong well formed twister taking out houses, toppling trees, etc. etc.

As I say, it did not hit us, but it was large enough and close enough that I could hear it. You know, that freight train sound. At first I thought the sound was continuous thunder that was so even and continuous that it sounded like one continuous boom, but it wasn’t that. There wasn’t any lightning, and it did not actually sound like thunder, so I gave up on that idea. Then I considered that it was an actual freight train, but for that to be true they would have to have moved the tracks from the west of my house to the southeast of my house. Not likely. I would have noticed.

I heard this as I stood in the open garage watching the rain, an iPad showing the radar Wundermap in one hand, my camera in the other. I could see the edge of a hooked-out storm cloud thought to contain, according to the weather service, a tornado pass to my left (east), on both the radar and in real time. There was actually blue(ish) sky to my right (west) which corresponded nicely to the radar signature.

The rain was very heavy, and the drops falling straight down, and there was not a whiff of wind. And then, suddenly, tiny pieces of vegetation started to fall as though they were part of the rain, from a level well above the standing trees in our neighborhood. This photograph is a sampling … actually, these are the pieces that fell nearest to me, unselected … of what came down.

I assume that this is tornado debris. These fragments of leaves, quite battered as you can see, could have come from anywhere up-stream along this tornado’s path, then spread out from the twister’s updrafts into the surrounding storm, where the calm air at the margin of the disturbance allowed them to fall with the rain back to the earth.

The following map shows the VERY APPROXIMATE track of the tornado, based on localities reported on the news to have been hit, and also indicates (“A”) where I collected the leaves in the photograph.
i-73f9156ad867d114104512137e0baf1a-stormtrack_leaves-thumb-500x722-65273.jpg

The leaves were collected approximately six miles to the west of the line drawn here. Given the size of the tornado, the vagaries of determining where updrafts would have been, and uncertainty of where the tornado actually tracked (thus far … this will be more carefully measured by the weather service), these leaves could have traveled anywhere from 2 to 6 miles laterally after being blown into the air by the storm, but in an oblique line running out from the tornado track of several miles longer. I quickly note that only leaves fell from the sky. Heavier debris clearly fell out long before it got here I also quickly add that we do not yet know if there was only one twister in this scenario. There probably was only one, but this awaits confirmation.

If there were any microorganisms living on the tree leaves on the west side of the Mississippi ’round these parts, they’ve been successfully dispersed to the east side of the river, in large numbers!

I know this is a small and irrelevant thing compared to the damage and destruction, and overall tragedy, that has happened in North Minneapolis and surrounding areas. But I thought the strangeness of it worthy of writing up and sharing.

More about tornadoes here.

Comments

  1. #1 Lynn Wilhelm
    May 22, 2011

    Greg, I’m glad to hear all of you are OK and that you obviously enjoyed the experience–I like interesting weather too.

    When tornadoes hit NC a month or so ago a high school yearbook was found in Cary, NC after the storms. The yearbook had traveled from storm ravaged Sanford about 30 miles away. And like your leaves, the book was dropped several miles from the nearest tornado track.
    Here’s a local news story about it: http://www.wral.com/weather/story/9474466/

  2. #2 Greg Lyon
    May 22, 2011

    Wow, I now believe that I heard the beginning of that tornado, Greg. Our house is about 1 MI due east of Cedar Lake. We were trying to decide what the sound was, sounded like a lot of airplanes taking off, but constant, and the wrong direction for the airport. It started to fade about the time we thought maybe we’d head for the basement. It seems strange that we experienced very little wind here so close to the start of it, and that we didn’t head for cover!

  3. #3 Greg Laden
    May 22, 2011

    Greg, that was it.

    Two more points, first a clarification. The line on the map is a composite of the track of the tornado on the ground (from it’s start in the south to just across the Mississippii) and the continued track of that part of the cell it came down from. That cell dropped a tornado along the northern part of that line at least once (caught on traffic cams).

    Second, Amanda just drove to a point about two miles closer to the track and saw significant architectural debris hanging from power lines. So, still two miles or so from the line, big stuff was coming down.

    Apparently there is a huge amount of debris all over North Minneapolis.

  4. #4 scidog
    May 23, 2011

    in South Mpls not far from Ft Snelling the view to the north west was impressive.even with heavy black clouds and sirens wailing you don’t really think that a tornado could hit your city.we had blue sky to the SE as a thunderstorm had passed over our part of town a few hours before and it felt like it was clearing.huge rainbow around 7:30 or so to the east.

  5. #5 Ana
    May 23, 2011

    From CNN: “Residents 70 miles away from Joplin in Dade County, Missouri, were finding X-rays from St. John’s [hospital hit in Joplin] in their driveways.” WOAH!

  6. #6 luckmervil
    May 23, 2011

    Ya really great post

  7. #7 Birger Johansson
    May 23, 2011

    I just got an idea to dispose of any future “End of the World” charlatans like Howard Camping.
    The next time someone decides to trigger suicides and murder-suicides with talk of the imminent rapture, we should hurry to the US, meet Greg and his posse and go tie down the charlatan in front of one of these twisters.
    The result will be literally heavenbound, thus making the prophecy true if only for one individual.

  8. #8 Greg Laden
    May 23, 2011

    Ana: Holy crap! So much for medical records confidentiality.

  9. #9 Calli Arcale
    May 23, 2011

    Not to be too flippant in light of the tragedy in Joplin, but will anyone inquire if God or the tornado is in violation of HIPAA? (Laughter’s important in times like these.)

    Only one fatality in Minneapolis, and it sounds like a bit of a freak accident. My heart goes out to their family. But my heart goes out so much more to Joplin, MO. What happened there is just shocking. Of all the things for a strong tornado to hit, a hospital….

  10. #10 Greg Laden
    May 23, 2011

    Update: In driving along north of where the twister crossed the river, but three or four miles from it’s central course, I observed quite a few pieces of house insulation, of various thicknesses, ages, styles, and colors (mostly pink or yellow) in fragments along the road. This material is not normally found evenly distributed along the road side for two or three miles. Almost anything can be found along the road, but not this, in this distribution. So there’s an “insulation zone” and a “ripped up leaf zone”

  11. #11 Tamara Sellman
    May 25, 2011

    Greg, 14 or so years ago we woke up to the same kinds of leaves plastered all over the south-facing side of our 2-story house. They had to be power-washed off the siding. Also, gumball -sized hail in the flower beds that didn’t melt off for several hours. This was in August in the far NW suburbs of Chicago. I learned later that there had been microbursts in our area.

  12. #12 UPDATE
    May 25, 2011

    A family in a town also off the path of this tornado experienced this: Still air, steady rain, no wind, and out of the heights of the sky came a patio door crashing into their backyard.

    Makes you wonder what happens in a region with few tornadoes, so no real knowledge of them (in the pre-modern era), and a tornado goes by undetected but does drop, say, a black bear or a giant fish or something on the village during a windless steady rain.

    Suddenly, there is a god. Or, at least, a cult.