LR doesn't delete images on it's own. So those images are still on your drive someplace, like where you placed them when you imported them or prior to importing them if you Copied them from a memory card.
More than likely the catalog file got corrupted when the power went out and LR then opened a backup. Check your drive for .lrcat and see if you have a newer version then what LR is now using.
Thank you for this. I still have to re-import a few folders, but after some looking around my hard drive, I did find my files. I did have to relaunch LR using a time prior to the improper shutdown. Furthermore, since I had to go back to an earlier date/time, I had to reimport some of my more current files. Nonetheless, so far this looks to be the right solution. Thank you so much!!!
You also need to get a UPS (Uninterrupted Power Supply) so this doesn't happen again.
Another tip to help with such occasions, looking forward, is to ensure (in the Catalog settings) Automatically Write Changes to XMP is turned on. This operates continually, as you do new work on images. This can also be done manually, at will, but this setting removes the need to remember to do so.
It is usually not a good idea to re-import images that you have imported before, until all other avenues have been exhausted; IOW unless you KNOW that you are now using a Catalog which definitely does not have them imported. For example: because you have needed to go back to an earlier Catalog backup dating from before your initial import of those.
The reason I say this, is that images can fail to appear in the expected place for various reasons, including that your view is filtered in some way so as not to show them, or they are physically not located quite where you (or LR) had thought they were.
That said, when you DO import images which have, at some earlier time, been worked on by LR - IF at the time of that earlier editing, Automatically Write Changes had been turned on - and/or IF then or later, the LR metadata was written out with Ctrl+S (Cmd+S) or the Write Metadata command - then this new second import will automagically cause the images to arrive with their earlier LR editing intact, including snapshots.
What you'll NOT retrieve is any virtual copies - also flags, Collection membership and maybe other things (that I forget). That said: there's a lot of editing that you won't need to repeat.