I'm wondering why you didn't secure it before the storm? In my neighborhood we have written rules that ANYTHING outside and not "nailed down" must be brought inside before a storm. Patio furniture may be thrown into the pool if you prefer. We even took the large hanging porch light down and stored it in our garage before Frances came through. Just common sense!
If you can't take the trampoline inside, then at least turn it upside down where it will be less likely to become a sail, and use stakes to secure it to the ground. And keep in mind that if your trampoline damages someone else's property or injures someone, you will be liable for damages.
Anne