I often rely on Firefox's cache to reopen pages I've previously visited while offline and more quickly load webpages. However, when Firefox is improperly terminated (such as by a hard computer shutdown caused by a power failure), the cache becomes empty. Why? Does it become corrupt, or is there some other technical reason? This question is platform-agnostic.
I'm not asking for speculation or opinion here, but an objective reason for this behavior. If this is by design, I'd like to see relevant references to discussions by Firefox developers or comments in the source code.