I have worked in 2 hubs over the past 20 years and each have been shut down twice. The first one was shut down mid day for the Rodney King Riots and all day for the Northridge earthquake. The one I am currently at was shut down twice on a "volunteer" type basis during two fire storms.
During the riots, they called back all the drivers. Unfortunately for me, the riots were taking place between my route and all around the hub. This was before diad, so I just kept delivering while I watched LA burn from the hills until I got the message from my first pickup at 1600 that they called us all back in. Luckily for me, the freeways were empty by that time since I was in a P400 with the little bicycle mirrors that fold in at 40mph.
When I reached the building, it was like a scene out of a surreal mad max type movie; total anarchy and chaos surrounding the building(buildings on fire, looters walking around with tvs, stereos, etc.). The bay doors of the hub were shut when I approached guarded by 4 guards with bats and batons. As I got closer, the doors opened up just long enough for me to enter the building before they shut tight again.
Getting to the employee parking lot was another adrenaline adventure. It was next to a low income apt. building that was on fire and looters were all over the place. The guards didn't want to escort me to my car. Finally, one got his car and took me to the lot. There were 5 cars still in the lot and surprisingly none were vandalized. Nothing around the hub was untouched by the riots(either burned, vandalized or looted) except the hub and the unguarded employee parking lot. It was as if UPS was the only respected place in that community.
The earthquake was the only time that my hub was completely shut down. It happened early in the morning before my start time. The only damage at my house involved a 27" tv falling off a tv stand. I called the center to see if I still needed to come in......no answer. So, being the well programed driver I am, I drove to the hub on eerie deserted LA streets during rush hour just in case the phone lines were dead. When I got there, the building was closed down and all the parking lots were empty; not a soul in sight.....it was creepy.
The fire storms never directly threatened my current hub except for unbearable air quality from all the smoke, soot and ash. The hub never fully shut down, and they only effected the routes inside the fire zones. No one was "forced" to work, but only a handful of hourlies chose not to.