Last week I wrote a blog on the Plague of Justinian and I thought it might be interesting to delve a little further into disasters of the ancient world in some future blog posts so I thought I'd dig some up to consider. At the risk of giving a spoiler, that plague rated as the number one disaster the listverse.com contribution "8 Natural Disasters of Ancient Times" here.
Also, while there is some overlap, lifestyle.allwomenstalk.com has put forth "Natural Disasters That Shook the Ancient World" here.
Finally, on mentalfloss.com, they take it in a slightly different direction with "11 Natural Disasters That Led to Wars" here. Some of these are from more recent times but it's all interesting nonetheless.