What if it was heavily raining in NYC during 9/11? Will the Towers collapse?

Let's say the hijackers still see the Twin Towers through the lower visibility and crash the planes into the towers.

If it was heavily raining in New York on 9/11, will the rains be able to help in extinguishing the fires that resulted from the impacts and prevent the heat-induced structural stress that weakened the structures and eventually resulted into the collapse of the Twin Towers?

I would say rain or no rain the towers would still have fallen if the planes hit. That is if the attack even happened with the rain and lower visibility. I would guess they would wait until it was a nice clear day before trying. If however they had to than with the little training they had they would likely hit something else killing far less people.

As for the fires inside the towers I don't see much happening. The fires were inside the rain would do little if anything to them. I saw a video testing would the towers fall due to the fire however I can't find it right now. But it showed that yes the fire would make the beams fail.
 
This depends on how low the ceiling was. If you had a really nasty day, the towers could be obscured by clouds making them nearly impossible to hit. In that case, provided that the hijackers checked weather forecasts, you surely would have had an abort that day. If they didn't check METARS/ATIS (weather reports), then you could have a hijacking and inexperienced "pilots" unable to break through a low overcast. It is a mystery what they would have done. If they were scud-running at 300 feet, you could have a much higher death toll from the WTC complex due to them being forced to hit at much lower floors.
 
As for the fires inside the towers I don't see much happening. The fires were inside the rain would do little if anything to them. I saw a video testing would the towers fall due to the fire however I can't find it right now. But it showed that yes the fire would make the beams fail.

Even if, like, the top floor of both towers were open (they were closed during the attacks so people were not able to go tops of the towers) and rain was pouring in from the opening?
 
Towers still fall if they are actually hit. The most significant difference I could probably see from this would be that they end up missing the towers (if it were particularly foggy that day) and head towards a completely different direction.
 
Even if, like, the top floor of both towers were open (they were closed during the attacks so people were not able to go tops of the towers) and rain was pouring in from the opening?

The fires and the hit itself would have likely have doomed the towers. But let's say the rain coming from the opening left after the planes hit the two towers did anything of note the beams would have likely failed anyway. One tower was hit lower than the other was. If I recall it was the second tower but I could be wrong in any case many people would have dead that dark day. Rain or no rain.
 
The biggest effect would be if the flights in question are delayed. If American Airlines Flight 11 is delayed, then more people will be in the North Tower and thus more casualties. If United Airlines Flight 175 is delayed, then more people in the South Tower will survive and possibly the flight will be intercepted and shot down or otherwise miss its target, leaving the South Tower still standing, assuming the North Tower still collapses.

Could the heat from the North tower have collapsed the South tower? WTC7 wasn't impacted and still fell.
 
This depends on how low the ceiling was. If you had a really nasty day, the towers could be obscured by clouds making them nearly impossible to hit. In that case, provided that the hijackers checked weather forecasts, you surely would have had an abort that day. If they didn't check METARS/ATIS (weather reports), then you could have a hijacking and inexperienced "pilots" unable to break through a low overcast. It is a mystery what they would have done. If they were scud-running at 300 feet, you could have a much higher death toll from the WTC complex due to them being forced to hit at much lower floors.
This. Even if the METARs were showing OVC010 (overcast at 1,000ft AGL), it would've been tricky because they'd have to descend just enough to be through the deck, but high enough not to risk hitting anything else. Think driving a moving truck for the first time down a narrow single lane construction zone with barriers on either side, and add a dimension and another 120mph or more.

An oops at this point could easily botch the job.
 
The fires in the twin towers were inside the buildings, so rain would have a negligible impact. The collapse of the towers was probably inevitable after the impacts, even though jet fuel can't melt steel beams. One big impact of rain, as others have mentioned, would be on the attackers' ability to find their targets. Another major impact would be on the dust clouds that came up after the towers collapsed. These clouds spread large amounts of hazardous materials all over Lower Manhattan and has resulted in significant impacts on the respiratory health of people, especially first responders, who were caught outside in the dust or worked in dusty areas in the following days. The cancer connection is somewhat more tenuous than the respiratory injury. Heavy, continuous rain on 9/11 would reduce the size of the initial dust cloud, clean a lot of the dust off the streets immediately, and then keep the dust (everything would be wet) down during the initial phase of firefighting and search & rescue at Ground Zero.

In a fire the smoke can act as a insulator preventing heat from escaping this could have gotten the aluminium airframe hot enough to combust.
 
Could the heat from the North tower have collapsed the South tower? WTC7 wasn't impacted and still fell.

To much distance. The heat necessary would be dissipated as soon as it left the walls of the tower on fire. Beyond that the concrete cover of the structural columns and beams would be intact on the tower not hit, insulating the steel as was intended.

The aircraft parts impacting compromised the concrete cover on the steel structure. Between that, the fuel burning, and any magnesium also in the aluminum burning the steel columns and cross beams were heated to failure temperatures. Note the melting point of structural steel, possibly A36 grade in this case is up around 2,800 degrees Fahrenheit. The failure temperature is far below that, possibly as low as 1200 degrees F depending on the load and tension.
 
Could the heat from the North tower have collapsed the South tower? WTC7 wasn't impacted and still fell.

7WTC was impacted, just not by an aircraft. When the North Tower (1WTC) collapsed a significant amont of debris from that building hit 7WTC, causing massive damage on that side of the building and starting the fires which would eventually bring it down.

If not struck the heat from the North tower likely would not have affected the south significantly.
 
In a fire the smoke can act as a insulator preventing heat from escaping this could have gotten the aluminium airframe hot enough to combust.

The parts of airframe in the tower fires would have burnt anyway, insulation or not. It's what aluminium aircraft structure does in a fire if allowed to.

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Even if, like, the top floor of both towers were open (they were closed during the attacks so people were not able to go tops of the towers) and rain was pouring in from the opening?

It wouldn't make a difference - a lot of the water would simply evaporate before getting near the fire.
 
This. Even if the METARs were showing OVC010 (overcast at 1,000ft AGL), it would've been tricky because they'd have to descend just enough to be through the deck, but high enough not to risk hitting anything else. Think driving a moving truck for the first time down a narrow single lane construction zone with barriers on either side, and add a dimension and another 120mph or more.

An oops at this point could easily botch the job.

An excellent analogy. Scud running at 500 knots is not for the inexperienced or the faint of heart. It would have been VERY difficult, even for a qualified pilot.

In theory, it could be done using constructed FMS waypoints, but that requires a knowledge of systems and advance planning that I don't believe occurred. You'd go out over the harbor, descend, and come in over the Verrazano bridge and up that way. The 767 FMS is pretty versatile, but even for line pilots this would be advanced stuff not used on a regular basis.
 

FBKampfer

Banned
Aren’t the fasteners the structural weakness in a steel construction? Under intense heat, and bearing structural load, aren’t the bolts/rivets holding the steel members together likely to fail first?

Ric350


Depends. The bolts and rivets are also likely to have the lower temperatures since they pass multiple beams to serve as heat sinks, as well as being located in the interior of the beams (and thus insulated to a degree by the thermal capacity of the surrounding materials).

As a rule, the less material, the quicker it heats up.


Structural engineering isn't my area of expertise, but I would assume the fasteners are of the same grade steel. This would be another factor.
 
Acording James Woods the terrorist did trial runs before the day.

I wonder why they didnt crashed in more populated towers too

No good argument will come out of a statement that begins with "According to James Woods" :D

There was something in the neighborhood of >10,000 people in those buildings before the planes hit them. My understanding is that the al-Qaeda plan did not anticipate the buildings collapsing from the fires.

(edited: to remove dumb speculation and insert actual data)

https://www.telegraph.co.uk/news/wo...den-didnt-expect-New-York-towers-to-fall.html
 
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No good argument will come out of a statement that begins with "According to James Woods" :D
That is a verified story, Mr Woods did reported some strange acting arabs looking guys in a first class fly mere month before 911.
 
I remember seeing that interview when it actually happened! That's the very thing that lowered my estimation of the intellect of James Woods (whom I love as an actor). All he saw was some Arabic guys speaking Arabic. That's it... zero connection to the 9/11 plot.
 

nbcman

Donor
Depends. The bolts and rivets are also likely to have the lower temperatures since they pass multiple beams to serve as heat sinks, as well as being located in the interior of the beams (and thus insulated to a degree by the thermal capacity of the surrounding materials).

As a rule, the less material, the quicker it heats up.


Structural engineering isn't my area of expertise, but I would assume the fasteners are of the same grade steel. This would be another factor.
Not necessarily. When I was installing sway bracing on conveyors in the San Francisco area many moons ago, the supports and bracing plates were the same steel as we installed at other but the bolts/fasteners that we used were grade 8 instead of grade 5 that were used at other sites. Had to load multiple barrels of bolts into the trunk of my rental car when I had to go buy the right fasteners for the earthquake prone area.
 
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