NOAA Report Cites Vertical Evacuation Plans

[Ixolib]

I believe some relative "high-rises" that partially collapsed in Ivan were built on a slab foundation rather than on piles. But, no matter the structure, I think it would be pretty weird to look out your window and see that your entire building is completely surrounded by water...

http://www.pressofatlanticcity.com/news/newjersey/030205RUN_M1.cfm

[Rainband]

wind gains velocity with height

[Derek Ortt]

vertical evac works wonderfully for a tsunami, but is a death trap for a cat 4 or 5 hurricane

[Ixolib]

vertical evac works wonderfully for a tsunami, but is a death trap for a cat 4 or 5 hurricane

Is the problem because of:
The wind?
Wind-driven waves?
Tidal surge?
Or all the above?

With the limited warning of a tsunami, seems this may be the only option for many. But, it also seems to me that ANY moving water at the base of a high-rise would be cause for concern (i.e. weakening of the structure) whether from a tidal wave or tidal surge.

[Cookiely]

Our main trauma hospital, Tampa General, is on Davis Island in Tampa Bay. The island is on the lowest evac order and most of the patients go home in the event of evacuation. The ones that can't go home get evacuated vertically in the building. There are two roads leading onto and off the island. I've seen both of them cut off by rising water not associated with hurricane activity. My question is will the vertical evacuation (there are nine floors) be safe in the event of a cat 3 or 4? I believe the hospital was built in the 1930's but there have been newer additions. Would the integrity of the building be in jeopardy?

[MGC]

Who can forget the highrises in Houston after Hurricane Alicia. Most of them had thier windows blown out. I would not want to be in a highrise during a major hurricane......MGC

[Persepone]

Vertical evacuation to higher floors sounds like a last resort unless there is something peculiar about the building (e.g., it is built into a hill or is on high groun) or unless there is a mechanism for evacuating people from that building to some safer location (elevated roadway or walkway to high ground and out? a helicopter pad? some other way to "buy time" to get out?).

There are some streets in big cities that could rapidly flood (sort of flash flood conditions) and then going into marked buildings and going UP could save you because what is ground floor on one side of the building may be 2nd or 3rd floor on the other side of the building. So yes, that makes sense. By going in to the building and up, you would quickly reach higher ground.

We used to own a house on a little ridge in CT and in 1938 and in 1955 the little row of houses that included ours became an "island"--but the houses themselves did not flood during those events. People were evacuated to them because they were on "high ground." (we have old photos) So perhaps there is a building that is a "high rise" that is also built on what is geographically "high ground" and then it might be the safe place to evacuate to--not because it is a tall building, but because of its location.

Assuming that a "high rise" is safe in high wind conditions or flooding conditions is a bad idea because yes the windows blow out, yes the foundations can erode, etc. Of course that does vary from building to building, but I'd think those would be refuges of last resort.

There is one place where "vertical evacuation" does make some sense--if you mean by "vertical evacuation" signs, steps, other things that remind people to go UP to escape rapidly rising water. Apparently the tendency people have is to try to outrun flooding--and perhaps they need to be reminded to look for a quick route to higher ground. There are signs like that in canyons, ravines, etc. to remind people to climb up... Makes sense!

Fairfield, CT has signs on main roads that warn of danger that would not be apparent to new residents, travelers. There is a stretch of Route 1 near MacDonalds where signage says if you are there during bad storm/hurricane, etc. you risk being under up to 12' of water--and the signs clearly tell you how to move to a safer place! That makes a lot of sense because hazards are not apparent--you don't realize how close you are to the water at that point. There are also signs in various other places that tell you that location floods quickly and again--how to get to high ground. Those make a lot of sense!

Perhaps the hospitals, etc. cited don't have a choice for some patients &/or the lesser of the evils is to move them to 2nd or 3rd floors. I guess if the patients would not survive evacuation, if it were too late to evacuate them safely, etc. then there is no choice but to have a "vertical evacuation" plan.

[Ixolib]

There is one place where "vertical evacuation" does make some sense--if you mean by "vertical evacuation" signs, steps, other things that remind people to go UP to escape rapidly rising water. Apparently the tendency people have is to try to outrun flooding--and perhaps they need to be reminded to look for a quick route to higher ground. There are signs like that in canyons, ravines, etc. to remind people to climb up... Makes sense!

That DOES make sense... Wonderful post - and thanks for the insight!