Burn it did not – but the data were gone nevertheless.
The head engineer at a data recovery firm once lost all of his personal possessions in a wildfire, so it was a little ironic what happened to one of his clients. The client had stored a rack of 96 hard disks underneath a fire-control sprinkler. One day, the sprinkler popped, probably due to a false alarm, and the disks were inundated with water. Most of that data was gone, since it had not been backed up.
This story illustrates that you should always store your data according to the 3-2-1 rule (at least 3 copies on at least 2 different storage media and 1 of those in a different location. Also, regular and reliable backup is key.