Strange noise in the dash.

So, I am on vacation in the islands.
Yesterday we were deep in the bush and were caught in a tropical rain storm.
Big Rain and deep puddles!

After a while the windshield started to fog so I cut on the fan/defrost thing.
I noticed that the normal noise that it makes was not there and was not blowing as hard as usual. So I cut it off.
A few minutes later I started hearing a whirring sound coming from in the dash on the drivers side. I turned the fan on and off and nothing happened.
Everything stayed working and after a while the noise stopped. I also looked under the hood but could not hear the noise. I am sure it must be under the dash.

What is under the dash on the drivers side that would do this?

Any ideas?

Thanks.

Maybe some debris,leafs etc. got caught in the fan blades and the sound just traveled up the pipes?