Wind and rain...
I worked for a large UK conglomerate in the late 80s and through the 90s.
Just before I joined, their Addlestone data-centre was in an old bus depot. One night it rained in Biblical proportions and the whole roof caved in. The ops were running round ankle deep in water and knee deep in rubble. The disaster recover procedures were well and truly put to the test that night.
In 1989 the second big hurricane hit the UK and in our little 2nd world war wooden cabins in Titchfield, the walls were flexing in and out and the windows were bowing. We were seriously thinking about going outside and driving home as it would be safer than sitting in this contraption built out of matchsticks!
Just then, I happened to look out the window and looked on in awe as the roof of the new data centre next door lifted up in the air in one piece, lifting up from one end, going vertical, then landing, in one piece, on its back in the car park, making pancakes out of the cars parked there.
We quickly rushed next door to see if anyone was hurt. The glass wall in the stairwell seemed to have been blown out and that caused an updraught that picked up the roof and smacked it down in the carpark. The data centre itself was still intact, but we found the office workers on the top floor still cowering under their desks. Luckily nobody was seriously injured, just very shaken. We took them back to our rickety structure and gave them coffee.
I was then sent back to the debris strewn office to see if I could find any license agreements and other important documents...
In the '87 storm, I was working at Portsmouth Station, on the pier, selling tickets from a porta-cabin perched on the waterfront, selling tickets for the Isle of Wight ferry. There were no trains to work that day (trees on the line), so I hitched a lift in one of the mail vans that was waiting at Fareham station to get over to Portsmouth station - we didn't realize at that time that it was a full blown hurricane with 112 Knot (~130mph) winds. Rescuing ferries and fastening loose pieces of buildings and walkways made the day very interesting.