I think Wilma had many localized Cat 3 microbursts

[zlaxier]

This was a phenomenon during Hurricane Andrew where small sections received 200mph winds. They are also caused downdrafts.

A lot of the damage we are seeing is not Cat 1 wind damage and cannot be explained. I think this phenomenon is also responsible for some of the Brickell damage. It would be interesting to compare the radar loops from Wilma, cell by cell and overlay that with the areas of the most serious damage to determine if this happened.

But here goes more evidence of extreme winds, FPL polls designed to withstand winds of 119mph downed throughout Miami-Dade and Broward.

http://www.miami.com/mld/miamiherald/13004990.htm

Posted on Wed, Oct. 26, 2005

Despite forecasts, wind damage more severe in Broward and Miami-Dade

BY JOHN DORSCHNER

jdorschner@herald.com

In southwestern Florida, where Wilma slammed ashore, damage to the power company's infrastructure was relatively light, but in Miami-Dade and Broward, after the storm should have lost power traveling overland, damage was much more extensive.

In South Miami-Dade, near the Miccouskee Indian reservation, 40 poles, meant to withstand winds of up to 119 mph, were downed. So were 40 in South Dade along Krome Avenue. Another 40 snapped in Miramar and 20 near Griffin Road.

[Scorpion]

I agree. What was odd was that the sustained winds would come from the north, but then I saw big gusts come from the opposite direction. Apparently some of these gusts were strong enough to throw around a huge dumpster.

[zlaxier]

This has happened many times in the past. Andrew was one. Celia over Texas in 1970 was another.

Hurricane Celia, Auqust 3, 1970: Hurricane Celia was one of the most destructive storms to ever hit Texas, with damages estimated at $1.6 billion (in 1990 dollars).

Celia became a hurricane on August 1 in the Gulf of Mexlco and intensified rapidly in 15 hours before it crossed the coast north of Corpus Christi, TX. As it moved over land, spectacular damage occurred from a "cluster of high energy winds of short duration," (also called downbursts or microbursts). The extreme winds raked across the residential and business areas in less than half an hour. It was estimated that winds reached as high as 160 mph for several seconds. During those disastrous seconds, incredible damage occurred at the airport and an adjacent mobile home park which was completely demolished.

[zlaxier]

Short 3-4 second microbursts of 130-150mph could have blown out all those windows in Brickell, Fort Lauderdale, especially since they were elevated a couple hundred feet in the air where the winds are higher anyways by one category. A microburst that is 130mph on the ground could be 150mph 200 feet up.

[zlaxier]

Celia hit as a Cat 1, btw. Cat 1 with 160 mph microbursts of wind.

[Derek Ortt]

best track has celia as a cat 3

What happened in Miami was classic cat 1 conditions. Legitimate cat 1 winds and glass high rises do not mix

[Sean in New Orleans]

It was likely small tornadoes blowing up all over....we had numerous tornadoes all over SE Louisiana and the Gulf Coast for Katrina. There were so many dropping all over they weren't even detected and recognized by the NWS.

[WxGuy1]

It was likely small tornadoes blowing up all over....we had numerous tornadoes all over SE Louisiana and the Gulf Coast for Katrina. There were so many dropping all over they weren't even detected and recognized by the NWS.

Hmm... I think a lot of people see vortices and automatically think "tornado", particularly in cities. Whenever you have strong winds blowing through buildings, skyscrapers, neighborhoods, etc, you have the good chance of very short-lived vortices developing in the wake of these buildings. Remember seeing "mini-tornadoes" near the corner of a building on a windy day -- you see leaves and garbage spinning around. Now, if you have stronger winds, you can have more intense vortices. I guess I should call these more turbulent eddies than anything. Tornadoes are pretty common in hurricanes, moreso the day or two after a system makes landfall, and there is some study into tornadoes associated with the extreme horizontal shear in the eyewall.

[tsunamii]

I went through Celia. Scarriest experience of my life.

[george_r_1961]

Wilma had numerous mesos in her right front quadrant and several TVS's (Tornado Vortex Signatures) as well. This could account for the areas of localized heavier damage.

[bvigal]

This is such a blantant example of misinformation, disinformation, sensationalism, and lies by the press. As many stated here, these are not unusual results for hurricanes, cat 1 and up. Tornados have winds up to 300mph for crying out loud!

Anyone who finds some high-wind damage and then blames "inaccurate forecasts" is a wiener. I'd say Mr. DORSCHNER falls in that category, and CONGRATULATIONS. He wins my Media Dope-Of-The-Month Award!

[terstorm1012]

It was likely small tornadoes blowing up all over....we had numerous tornadoes all over SE Louisiana and the Gulf Coast for Katrina. There were so many dropping all over they weren't even detected and recognized by the NWS.

Hmm... I think a lot of people see vortices and automatically think "tornado", particularly in cities. Whenever you have strong winds blowing through buildings, skyscrapers, neighborhoods, etc, you have the good chance of very short-lived vortices developing in the wake of these buildings. Remember seeing "mini-tornadoes" near the corner of a building on a windy day -- you see leaves and garbage spinning around. Now, if you have stronger winds, you can have more intense vortices. I guess I should call these more turbulent eddies than anything. Tornadoes are pretty common in hurricanes, moreso the day or two after a system makes landfall, and there is some study into tornadoes associated with the extreme horizontal shear in the eyewall.

http://earthobservatory.nasa.gov/Newsro ... mg_id=4487

I imagine it's a lot like Island Vortices...the wind gets disrupted by whatever is in its path and forms eddys.

[Windy]

It was likely small tornadoes blowing up all over....we had numerous tornadoes all over SE Louisiana and the Gulf Coast for Katrina. There were so many dropping all over they weren't even detected and recognized by the NWS.

Hmm... I think a lot of people see vortices and automatically think "tornado", particularly in cities. Whenever you have strong winds blowing through buildings, skyscrapers, neighborhoods, etc, you have the good chance of very short-lived vortices developing in the wake of these buildings. Remember seeing "mini-tornadoes" near the corner of a building on a windy day -- you see leaves and garbage spinning around. Now, if you have stronger winds, you can have more intense vortices. I guess I should call these more turbulent eddies than anything. Tornadoes are pretty common in hurricanes, moreso the day or two after a system makes landfall, and there is some study into tornadoes associated with the extreme horizontal shear in the eyewall.

BTW -- storm chasers like to call these non-tornadic ground circulations "gustnadoes". You see a lot of them in supercells, especially in strong RFDs. They're definately not harmless, but they're usually not as destructive as tornadoes.

[sponger]

I dont know about Miami, but the the winds in Broward were definately higher. The damage reminds me of Andrew away from the eye. More trees down than I have ever seen, alot like Charley in Orlando last year. Cars flipped in Pompano Beach and skyscaper damage similar to Katrina in New Orleans. S Fl will not look the same for a long time to come. When was the last time anyone ever saw 95% power outage over a 100 mile swath?

[jasons2k]

I definately believe it. We had some localized microbursts during Rita. I was outside at one point and the wind came down vertically in gusts at times as opposed to horizontal. We also had a lot more trees down in my immediate vicinity than the surrounding area.

[Logandear]

So are there any "true tornadoes" in a hurricane? I've read that tornadoes spawned from hurricanes are formed differently than tornadoes spawned from a supercell - that those spawned from hurricanes are caused by friction with buildings and land structures. But how does that explain waterspouts (if you'd even call them that) during a hurricane? For example, there was one spotted on radar offshore headed toward Big Pine Key Sunday night ("a violent waterspout"). How about the ones actually spotted on radar by the weather center? Would those have been considered "true tornadoes?" I don't know much about the dynamics of "regular" tornadoes, so this might be a stupid question. I have much to learn.

That said, I was in Tampa during Dennis this summer and there was what's believed to be a "downdraft" or "microburst" down the street from us. It didn't travel far at all - maybe a few hundred yards. And the damage was in a fairly narrow swath, and not too extreme (compared to the tornado damage I've seen, anyway!).

[george_r_1961]

So are there any "true tornadoes" in a hurricane? I've read that tornadoes spawned from hurricanes are formed differently than tornadoes spawned from a supercell - that those spawned from hurricanes are caused by friction with buildings and land structures. But how does that explain waterspouts (if you'd even call them that) during a hurricane? For example, there was one spotted on radar offshore headed toward Big Pine Key Sunday night ("a violent waterspout"). How about the ones actually spotted on radar by the weather center? Would those have been considered "true tornadoes?" I don't know much about the dynamics of "regular" tornadoes, so this might be a stupid question. I have much to learn.

That said, I was in Tampa during Dennis this summer and there was what's believed to be a "downdraft" or "microburst" down the street from us. It didn't travel far at all - maybe a few hundred yards. And the damage was in a fairly narrow swath, and not too extreme (compared to the tornado damage I've seen, anyway!).

Tornadoes forming off of tropical cyclones from due to strong shear, the same as the tornadoes that form out of a frontal system. The difference is the shear caused by a tropical system is due to the winds at the surface slowing down while winds aloft remain quite strong. Get a landfalling tropical storm interacting with a cold front and you can get some strong tornadoes.

[Jim Cantore]

I can agree with this

Damage on Marco Island was rather light from what I heard but inland it was worse

I can buy this

[Tampa Bay Hurricane]

I can also buy this microburst phenomenon. I have seen damage where
certain areas receive a lot more than they bargained for in past
storms...severe microbursts or tornadoes most likely...
I am not surprised by the extreme bursts of wind...I had one
during Wilma even though I was located over
100+ miles NW of its center...it was the worst
blast of wind- in fact it was the worst weather event I have ever experienced...blew up generators and snapped trees in half...and
those trees were uprooted in a blast that followed 5 minutes later...

I wasn't expecting to see that with a forecast of 45 mph gusts...
what I saw seemed to be a bit stronger to say the least...

I know what I saw....unless someone surreptitiously got me
drunk Monday morning...

Wilma was one Mean Bean Machine....

[StrongWind]

Most of the heavy damage I've seen, at least at first glance, appears to be straight line rather vortice based. Things such as rows of trees al fallen in the same direction, planes filipped the same, debris fields, etc.