Weird noises

It's really grim here today. It's been raining pretty much all day, and now the wind has picked up as well. They are saying that overnight tonight and all day tomorrow is going to be the worst storm of the year so far. Winds of 80-90mph and torrential rain.
The weird part though is something totally new to us.
Every time there's a gust of wind, the chimney (which is blocked up) is acting like some kind of weird amplifier and generating this bizarre noise. It's kind of like when you blow over the rim of a bottle, but much louder.
We've lived here for 10 years and this has never happened before.