local folders shown in Outlook but 0 kb in size and seem empty, while Identity folder is still 16 Gb

I had a ton of emails in local folders in Outlook 2011 (latest updates, Mac OS 10.6.8). I now still see the folders, but they seem to be empty - Outlook shows them as as if they had no contents. Since the Identity folder is 16 Gig in size, I think the info is still there somehow - how do I get my local folders and their contents back??