Most Senses are impaired during a firefight --
Touch is covered up by thick gloves.
Seeing is obscured by smoke.
Taste, well, I hope you never taste anything!
Smelling is blocked by the SCBA, once it's donned.

The only sense that remains more or less at full function is hearing, blocked at most by only a thin layer of the Nomex hood if you're wearing one, and only impaired by all the different sounds you may be hearing at once.

What is the most memorable thing you've heard on a fireground, something you said to yourself, "Gotta remember that one!"

For me, that sound was back in 1989. We had a 600'x50' single story chicken coop about 50% involved. Myself and another FF where on the line that stopped the fire spread -- a portable master stream at 350gpm we got at a low angle and pointed under the eaves.

All of a sudden, we heard a large, unusual noise. It wasn't an explosively loud "pop" as much as a long, big "rumble" and "whoosh" sound.

We looked at each other, and said, "What the F?" And started looking up and down the building. Finally Dan pointed up at the eaves -- which where now pointed UPWARDS -- about 200' of the truss roof had collapsed at like dominoes which was the "rumble" and the "whoosh" as the roof came down pushing the air out of the building.

It was nothing like I had ever imagined a roof collapsing would sound like, but it's something I'll never forget for a unique sound!

Sounds, sounds, everywhere are sounds...