Tom, do what Velcro says and noise train her. I've never seen a dog that can't be trained to tolerate noise. Get someone to help you and find an old snare drum, tin pot, tin wash basin or anything that will make noise when your helper beats on it. Put you dog on a leash and TIGHT collar.
Have your helper start beating on the whatever while you lead your dog around it. Everytime you make a complete circle, give her a treat and highly praise her. Then start closing the circle in and repeat until you can get right next to the noise maker. When I do this in training the dog invariably ends up taking a treat from the top of the snare drum I use. Of course, don't beat on it when he is doing this.
After all of this, stay alert for the firecrackers or thunderstorms with plenty of treats and praise on hand.
There are four reasons a dog won't do something for you: Fear, Ignorance, Choice and distraction. This is a fear case so she needs plenty of consoling and praising that "it's alright"., etc.
Bill