I always thought that was more an expression of how when the adrenaline is pumping and your body is in full flight or fight mode (as it gets when things like this happen) then the whole world just melts away and all there is is the emergency you're dealing with. Not a literal statement of fact about the weather or fauna.
I'm sure it very much seemed like there was no sound to her because every one of her senses was dealing with this emergency.
(eta and getting across that no, she hadn't heard anything like WT screaming "mummy" or anything really obvious)