When we had the fast-moving line of thunderstorms with a bow echo move over MPLS today, several folks mentioned some words I didn't know - derecho and mesocyclone. We often get these kinds of storms in the summer that come through very fast, often going about 50mph or faster.
I read a lot today and found out that what we had today was a derecho. However I was lucky enough to be in an area that did not have the highest winds.
I was surprised to find out that an experience I had in 1998 was actually a very widespread destructive derecho that affected several states. All I knew all this time, before today, was that the Twin Cities area was affected. We had power outages for several days after, and there was so much damage where I lived that I guess I never did find out about the entire storm path. There were hundreds of trees uprooted where I lived, roofs blown off, very large light poles down the main county road bent completely over. I spent one day driving around taking a lot of photos and then had to go back to work. I think I must have been too busy to spend any more time reading about it.
I found out from reading tonight and learning about derechos, that it went through several states, in fact went all the way from MN to NY!
I also found out that about 12% of the total 300million in damages was done in my county in MN, Dakota Cty, which was one of the hardest hit areas.
I was caught out in this derecho. At the time I assumed it was a big line of thunderstorms. I knew the wind was at least 90mph from my experiences with hurricanes. When it first hit it did seem like it was over 100mph. I just assumed it was a strong thunderstorm with what I knew to be called straight-line winds. One thing that I read today explained something I never did understand at the time, which was that the winds lasted quite some time. The very highest winds lasted at least the first 10 minutes, and there were high winds very close in intensity for at least another 20 minutes. I had thought that when a thunderstorm downdraft hit it would go by pretty fast but this one definitely didn't. I never did understand why that was at the time.
That evening I'd gone out for a late dinner at a local Baker's Square. I left pretty late sometime around 10 or thereabouts and as I was leaving the waitress ringing up my meal said that there was a storm coming. We often get lines of thunderstorms so that didn't seem like any big deal. Driving home, which was only a mile away, the electricity went out. I found out later that's why the sirens never went off.
There was a lot of lightning in the west and when it lit up the sky it was a very distinct green. I got to the bottom of the hill (my apt complex on the top), and big raindrops started falling. The car ahead of me went slower and slower which was really annoying because I wanted to get home before the rain got worse. Finally I passed them and went up the hill. At the top was nothing but forest (although now a lot of it has been cut down for condos) where the road turned before going to the apt complex.
Just as I got to the top of the hill, suddenly 90mph plus winds hit and the trees started swaying wildly. I was completely astonished. The rain then came down and between the two I could no longer see the road ahead of me, in fact could not see at all, so I stopped, too surprised to think really. Suddenly a tree fell nearby and one of the large branches slammed against the car with a very large noise. I realized I wasn't in a good spot and that another tree could come down on the car and crush me and I wouldn't have any warning, and so since I knew basically where the road went even if I couldn't see it, boy did I have my foot on the gas pedal fast and I was going and didn't stop until I got out of the trees.
I couldn't pull into the underground garage because the power was out and had to park in the lot outside. I sat in the car and it was lightning constantly, the wind was blowing, raining hard, and after a couple minutes and it wasn't getting better I knew I'd have to get out and make a run for it to get to the apt. It didn't take me more than a minute but I was completely soaked.
Later on, very early the next morning, I drove to see where the tree fell. I couldn't believe it, but it had fallen only at most 10 feet from my car.
Everywhere, on every road, practically all over town, was the insulation from all the roofs that had gotten blown off, entire trees down, branches simply everywhere. It was a real mess. The most amazing things were the street light poles that were maybe 8 inches in diameter folded right over. The saddest thing was so many beautiful trees were gone, just hundreds of them.
It was such a surprise today to read about it. Now I'll know when I see those bow echos racing across MN all summer that it's a derecho.
Did some more reading today and I found out that for a reason that no one can identify, MN does have more derechos than anyplace on the planet. Hmmm...like I said earlier, I didn't know what it was called but we get these fast-moving bow echo storms all summer long here.
Edited by Margie (Sun Jul 24 2005 06:17 PM)