Okay, now here's something, from Engineering News-Record, which sounds more authoritative than publicoccurrenc.blogspot.com. 

The caption to this photo reads,

A chain reaction, beginning with the at-grade outdoor parking between the lobby area and the pool deck, may have resulted in the progressive, or perhaps disproportionate collapse, of the east-west wing of the tower, which contained 12 stories and a penthouse. The slab dropped one level due to punching shear (circle).  

It's something, I don't know what it means, but it is something.

Allyn Kilsheimer, founder of KCE Structural Engineers. Kilsheimer, who arrived at the site a day after the June 24 debacle, is working for the city of Surfside, north of Miami Beach.

...

“There may have been three collapses,” in quick succession, Kilsheimer speculates. Determining “why this happened is a long process of collecting data and creating computer models,” he adds.

Surface Parking Zone of Interest

An area of interest is the surface parking zone near the lobby entry drive that goes partly under the remaining wing. That slab for the parking, which is next to the grade-level pool deck, is the roof of a one-level basement garage that fills the site's entire footprint.

I thought a "slab" was on the bottom of whatever space it encompasses, not the roof. "slab for the parking zone"...is "roof of basement garage." I don't understand. Is the fucking "basement garage" not the goddamned "parking zone"?

According to Kilsheimer, it appears, from the position of the cars that dropped a level—one car’s nose ended up pointing to the pool area—that the lobby slab columns moved sideways toward the pool deck, causing the pool deck to drop, which then pulled on the tower columns, causing them to fail. “This will not prove where it started,” he says....

Here's the money shot:

However, Kilsheimer has all but ruled out an overload from the parked cars as the trigger. “It could be that a drunk driver hit a column,” he says. “We don’t know yet.”

WHAT WAS THE "EXPLOSION" NOISE?!

Is there precedent in your field for a DUI driver of a standard issue automobile hitting a support post and pancaking a modern building in America or other advanced Western Civ. country? I’m asking. Cite me to it if there is. Given the “shocked” reaction of your fellow engineers to this collapse, I would think they would want that citation also. 

If there is such precedent then please point me to the sources that support a drunk driver hitting a column in this case. Did any witnesses see a vehicle hit a post? If so, who? I am aware of none. Was a body found inside a vehicle? Hitting a reinforced concrete post with force sufficient to take out the post (or posts) would seem likely to addle the faculties of the already impaired driver. If he was conscious afterwards, did anybody see a drunk staggering away from the scene?

Because, and I will confess to you my suspicion, if this is the first time in the history of modern first world countries that you are aware that this has happened and you have no evidence whatsoever of a drunk hitting a post,  then I think you are pulling this theory out of your ass.

Wait. So was there more than one level to the parking garage zone thingy?

The caption to that photo is,

The collapse may have started in the at-grade parking area alongside and under the elevated first occupied level of the remaining wing (at right, in photo) and brought down the adjacent pool deck. The deck likely sent a shock wave toward the east-to-west tower, which then collapsed into a pile of debris. 

I don't understand, maybe its too late or I'm too stupid.

Sequence of the Debacle

In terms of the sequence of the debacle, there are reports of eyewitnesses hearing noises around the grade-level elevated pool deck and surface parking areas. Photos show part of the pool deck dropped onto the basement garage slab underneath it. The collapse would have sent a shock wave through the floor system at grade level, which is the garage roof, says S.K. Ghosh, president of S.K. Ghosh Associates LLC.

 What, in your opinion, would be plausible cause of BOOM!?

The pool deck is grade-level and the surface parking areas are grade-level is how I understand that.

Part of the pool deck dropped onto the basement garage slab underneath. So the pool deck collapsed onto the support slab of the basement garage. That sent a shock wave at grade level which is the garage roof. Okay! I get that. 

In this scenario, the shock wave was large enough to take down one or two critical columns, he adds. “From there, it was a progressive collapse.”

The shock wave would take out reinforced concrete support posts? Where does the DUI fit in?

I, Benjamin Harris, Noted Idiot, don't buy that. It sounds like they get to a certain point and then go, “After that it's progressive collapse all the way down.”It sounds like a catch-all.