What could cause all computers and servers to BSOD and restart?

Almost all of the computers on the company's network showed a bsod and restarted. Most of the servers seemed to restart aswell. Not exactly sure what caused it. But my best guess is a power surge.

For context, we recently got rid of our ups since it's old and we're currently waiting for the new one to arrive soon. However in the meantime, we're running on street power with a few generators for backup until the install. Is there a chance a building wide power surge could cause this? Or is it something else?

Event viewer just said it shutdown unexpectedly on all the PCs/servers I checked.