Nature Unleashed: Inside Natural Disasters is another excellent online (and real-life) exhibition at the Field Museum in Chicago.
Much of it is accessible to Intermediate English Language Learners. I especially like the E-Cards that students can send for posting on an online journal or blog.
We teach a unit on Natural Disasters in our mainstream ninth-grade English classes, and this site will be a useful addition to that section on my website. You can find this link, and many others, under the Natural Disasters section.