The legal definition of Storm is 'a violent disturbance of the atmosphere'.
In the days before insurance companies were banned from operating a tariff (price ring), most policy wordings were identical. Complex and not in Plain En glish, at least they were consistent.
Nowadays, you get what you pay for.
However, the policy will define what constitutes 'the buildings' and I'd expect it to include all outbuildings but maybe only those constucted of brick and/ or stone etc. so possibly a wooden or flimsy corrugated iron garage may not be covered.
.