Good lord. That is, in my eyes, simply unacceptable.
Is it because the structure isn't complete, therefore it doesn't have the strength that a fully-built coaster has? I just would have thought the structure would be strong from the first part built to the last.
It damn well SHOULD be. The partially completed structure should be able to withstand all of the loading conditions that the completed structure is able to (with the exception of the dynamic train loads, of course) - otherwise you're building a death trap.
If this does turn out to be a result of the weather, I see one of three things has happened:
1. The wind was so extreme that it went over and above the designed conditions for the structure (in its partially built state) - seems unlikely to me given the factors of safety in these sort of things.
2. The structure wasn't designed properly for it's temporary state.
3. The structure wasn't built properly for it's temporary state.
I hope the first is the case, as realistically it's the one most 'out-of-the-hands' of the designers/builders. If the latter two, RMC/whoever-is-helping-them-locally has a lot of questions to answer. Well, a lot more questions that if it's the first, in which case they will still have a lot to explain.
Hopefully no-one was hurt. That's the best we can hope for.