The Mystery of the Initial Floor Collapse of WTC1

The sequence of the WTC1 collapse can be seen fairly well in this video.

The following stills show the very early stages of the WTC1 collapse from the same angle as the video I linked to above:


Frame 1 


Frame 2 


Frame 3 

The front face of the building is where the plane went in-- you can see the dark irregular "scar" starting right above where the building facade is undamaged.


Frame 4 


Frame 5 

What the first three pictures show is a line of puffed out smoke that goes along one whole floor at the upper part of the plane entry hole.

The puffed out smoke most likely is from where a floor is collapsing onto another floor-- resulting in the smoke being compressed and being forced out the windows.

This sequence of stills tells us two important things.

First, the very first collapsing floor landed on a solid floor below it (otherwise the smoke would not have been compressed and been forced out), and this lower floor was closer to the entry hole than the collapsing floor. So this is odd, because one would expect the floors closest to the entry hole, where the plane went and where the fires should have been most intense, would collapse first.

Second, the first floor collapse only puffed out SMOKE-- not fire. One can see fire shooting out significantly as the collapse progresses in frames four and five. But one would expect the heat to be most intense where the fire was. Smoke alone puffing out would indicate either a dying, smoldering fire or that the smoke came from somewhere else. So-- if the floor collapse was induced by HEAT, why didn't fire come shooting out as the floor above the fire collapsed?

This sequence of shots would seem to indicate that the initial floor collapse was not caused by heat!