Are Miami high-rises in danger of collapsing in Cat 5 winds?

[Ptarmigan]

I tend to agree with this. I think plenty of buildings would be gutted, but I don't think many would totally collapse. One thing that happens when the windows fail is that wind is able to pass through the building, thus taking some of the stress off of the structure. When Hugo hit here, I remember that people who had solid wood fences lost those, while chain link fences remained (except those that were hit by something like a tree). The reason is that the wind had nothing to push against to cause those chain link fences to bend or fall.

I don't want to be inside a high rise during any hurricane. It will be shaky and make me feel seasick. Also, getting hit by glass is painful.

[Derek Ortt]

If you are going to stay in a highrise in a major hurricane... I'd be sure to have a parachute

[windstorm99]

A highrise is not a place you want to be in a major hurricane as the futher up you are you could easily have winds 1-2 categories stronger.

[Extremeweatherguy]

If you are going to stay in a highrise in a major hurricane... I'd be sure to have a parachute

I doubt that would be much help. lol. Trying to use a parachute in major hurricane force winds would likely be just as bad as going down with the building itself.

[hawkeh]

Base jumping in 150mph winds... No thanks.

[Derek Ortt]

you wont be going down with the building

You'll likely be sucked out along with the contents if you stay in a high rise in a major. A chute may provide some assistance, though not much

Moral of the story... leave a highrise in a cane

[Beam]

I hate to bring this up,but....remember 9/11 and the Twin Towers????

No offense, but a Boeing 767 ramming into the middle of a skyscraper at several hundred miles per hour with fifteen thousand gallons of jet fuel to ignite is in no way comparable to a Category 5 hurricane exerting it's force on a skyscraper. Two different sets of physics at work there, and they affect the buildings in different ways. There's no way to know what will happen in a category 5 until it actually DOES happen.

[Opal storm]

I wouldn't even be in a high rise in a category 1. A lot of builings with upper floors were severly damaged here in Pensacola during Ivan.

[Extremeweatherguy]

another thing to think about is debris. What if, for instance, a large chunck of another structure blows off into a skyscraper? In that case, I think the chance of collapse goes way up. It all really depends on the situation at the time of the storm.

In Miami's case in particular..those cranes they have out there right now would certainly be an issue to consider were a major to hit head on today.

[Ptarmigan]

If you are going to stay in a highrise in a major hurricane... I'd be sure to have a parachute

Even with a parachute, you would end up pretty far away.

[Ptarmigan]

I hate to bring this up,but....remember 9/11 and the Twin Towers????

The World Trade Center had massive explosion and violent inferno to contend with, which caused them to melt into violent dust and smoke cloud , unlike a Category 5 wind would do. I try not to think about that day, but unfortunately I still do, even more than five years have past.

[Derek Ortt]

a collapse in a hurricane of a high rise may be far worse than the 9/11

The WTC collapsed downward. If the Katrina NWS advisory were to come true, the high rise may tip over. That is basically an oversized cruise missle hitting the center of the city

[zlaxier]

I think high-rises more than 30 years old would be most at risk of collapse, especially those that haven't been maintained very well and are close to the ocean like many of those on Miami Beach. I think if a Cat 5 hit Miami Beach many high rises built in the 1970's and before would probably collapse into the sea from a combination of storm surge, wind loads, and weakened support columns from decades of Salt Water air corrosion.

[Recurve]

A co-worker told me about his experience in a highrise on Key Biscayne during Wilma. They were on the 17th floor I believe. The building swayed sickeningly, and they were trapped -- no elevators, and to get down they would have had to go outside to use stairs, and they couldn't go outside because they feared being blown off the open walkways.

I worry that thousands of people in south florida who don't know much about hurricanes will feel safer high up in a hurricane, until they find out how much worse the winds are, how fragile the glass curtainwalls are, and how their escape may be cut off.

[MGC]

One day the Miami Beach front won't look the same. It will sorta look like the Mississippi Coast after Katrina. The power of the water will destroy all in its path. The wind damage will be an after thought. Think of the mess when all those condos and hotels that line the water are destroyed by huge waves. Any building that does survive will have to be torn down because the one-two punch of the wind and water. Miami will one day replace Katrina on the most expensive hurricane strike. It is just a matter of time......MGC

[CrazyC83]

Have any high rises dealt with an F4 or F5 tornado? Would that be a good estimate for the damage?

[CrazyC83]

One day the Miami Beach front won't look the same. It will sorta look like the Mississippi Coast after Katrina. The power of the water will destroy all in its path. The wind damage will be an after thought. Think of the mess when all those condos and hotels that line the water are destroyed by huge waves. Any building that does survive will have to be torn down because the one-two punch of the wind and water. Miami will one day replace Katrina on the most expensive hurricane strike. It is just a matter of time......MGC

And yet that storm surge would not penetrate nearly as far inland, except along river valleys and channels, due to Miami Beach and other barrier islands holding back the ocean (and deep water offshore which means it wouldn't be as high to begin with). I estimate the surge at Miami Beach should a Category 5 hurricane the size of Katrina hit would be about 17-21 feet. Andrew was 16 feet at Biscayne Bay but it was a much smaller storm.

[zlaxier]

I estimate the surge at Miami Beach should a Category 5 hurricane the size of Katrina hit would be about 17-21 feet. Andrew was 16 feet at Biscayne Bay but it was a much smaller storm.

Because of the deep water offshore of Miami Beach, 10-12 feet is more likely what would result in a Cat 5 Katrina sized storm.

Because biscayne bay is shallow, 15 feet - 20 feet of surge would hit the mainland.

[MGC]

What is the elevation of the island Miami Beach is on?. Seemed rather flat last time I was there.....MGC

[Derek Ortt]

Miami Beach is fairly flat, though the surge should not cover the entire island.

When Jeanne, somewhat similar in size and intensity to Katrina at Mississippi, struck central Florida, the maximum storm surge anywhere in Florida was a whole 6 feet. The coastal condos were wrecked (the few that survived Frances, which produced an even lower surge), but the surge did not go that far inland. The lack of surge is why I feel safe riding out canes on the Rickenbacker Causeway.

Miami itself, especially Coconut Grove, has a fairly high ridgeline very near the Bay, so while the surge would be higher, it wont be going that far inland. Unfortunately, we can get winds of the EF3 to EF5 in gusts in hurricanes