39:04 As the buildings fell, they darkened Manhattan, filling the air with billowing clouds of dust and ash.

What produces these huge, scudding cauliflower-like masses of slowly moving dust?

39:31 True, a 110-story building has just been reduced to a million tons of rubble ... but is there anything in our experience we can compare it to?

39:44 A volcano.

This is the most disturbing section in the whole of 9/11 Mysteries. This is due to the fact that 9/11 Mysteries is often passed off as “more scientific than other 9/11 movies”, “accurate” and “unbiased”. That says a lot about 9/11 conspiracy theories in general.

9/11 Mysteries asks the question “What produces these huge, scudding cauliflower-like masses of slowly moving dust?”, and attempts to answer the question themselves. Before we debunk their answer, we will provide our own.

The dust cloud we saw on 9/11 was a density flow. A density flow is a mixture of debris particles (eg. dust) and air much denser than normal air. Density flows, whether in air or water, can maintain their form for much longer than regular clouds of dust.

A density flow will run out of momentum over time. Once it loses momentum, it stops moving. The denser parts of the flow will settle out and the lighter parts will mix with the surrounding medium.

Density flows can flow over water, or even in water.

Now that we know what did occur within the dust cloud on 9/11, we will now look at why a pyroclastic flow was not present. First, we must note that pyroclastic surges are exclusive to volcanoes and only volcanoes. This is a strict scientific fact. You cannot achieve a pyroclastic flow in any environment other than a volcanic eruption.

39:57 911 Eyewitness narrator: “The US Geological Survey website provides us with a definition of a pyroclastic flow as a ground-hugging avalanche of hot gas and debris. The rising gas chimney is clearly visible in this photo of the North Tower implosion, with pyroclastic flows between buildings. The cauliflower shape of the debris cloud is a telltale sign of pyroclastic flows generated by massive explosions, typical of volcanic eruptions and controlled demolitions.”

Reporter on radio: “This is the second building that has gone down…”

911 Eyewitness narrator: “A pyroclastic surge can even flow over water as hot gases carry dust created by explosive energy. Here, the South Tower implosion creates a pyroclastic surge, moving out over the Hudson River.”

The US Geological survey website does indeed provide us with a definition of a pyroclastic flow. Let’s read it.

So, we are supposed to believe the cloud created by the collapse of the Twin Towers was moving at over 100 km/h and had temperatures sufficient to carbonize wood? We are talking about a dust cloud that would have been over 500°C moving through New York City and causing no damage whatsoever.

The dust cloud was described as hot, but that was by people in the middle of it. That rules out the 500°C option. Quite simply, no one anywhere near the World Trade Center complex would have survived a pyroclastic flow floating over them. Nevertheless, what about speed? 9/11 Mysteries itself notes that the dust cloud was “slowly moving”. Therefore, that rules out the 100 km/h option. Not looking good for the “Pyroclastic Surge” case at all, is it?

The extract from 9/11 Eyewitness that we are shown states that the cauliflower shaped clouds are a sign of a pyroclastic flows. This is wrong. If you carefully examine the comparison photos we are shown, you will note that the clouds coming from the World Trade Center appear to be much lighter in color and density.

Now that the assertion that a pyroclastic flow was present on 9/11 has been debunked, we will examine the outright lie that 9/11 Mysteries displays to us via 9/11 Eyewitness. We are told that pyroclastic flows are “typical of volcanic eruptions and controlled demolitions”. This is quite simply a lie. No pyroclastic flow has ever been observed at the site of a controlled demolition. In fact, no pyroclastic flow has ever been observed outside a volcanic eruption.

40:55 A volcanic eruption produces exactly the same thick, scudding ash – heavy with debris, hugging the ground as it flows out from a tremendous internal explosion.

First to note is that we were shown a few pictures in 9/11 Mysteries that compared a volcano to the collapse of WTC1 and WTC2. As we previously noted, the cloud from the volcano is clearly much darker, thicker and higher in density.

The effect of a pyroclastic surge is a result of the heat within the volcano created by molten lava. This effect cannot be recreated by thermite (as 9/11 Mysteries appears to suggest). 9/11 Mysteries seems to imply that “tremendous explosion = pyroclastic flow”. Again, an over simplification. 9/11 Mysteries “pyroclastic surge” thesis is based on a lie by 9/11 Eyewitness and bad science that fails to take into account the possibility of logical explanations.