How about some good sized shop fans blowing against the fabric. The vibration(flapping)from the air should prevent a lot of the snow from settling on the fabric...bonus...in summer will help cool the place.
Edit: Briefly looked at a site that specializes in air supported dome fabric buildings, they suggested dragging a fairly heavy rope over the structure to dislodge the snow. With a building your size...you'd have to use a lighter rope with a weight on one end to throw over then use it to pull the heavier rope over. Two guys should make quick work of it.
If you do go with the AVS approved audio option, maybe a horn-loaded sub that can project/direct the sound waves would be a good idea. Run some fr sweeps and see what gets the structure resonating/excited.
Last edited by KenWH; 02-23-2018 at 03:20 PM.