hi! not discouraging other responses, but fyi, there have been a few questions about natural phenomena occurring during/before battles, so you may find some interesting examples in there

• Has there ever been a natural disaster (earthquake, volcano, flood) that took place during a military engagement?

• Have there been any natural disasters that have changed the tide of war between nations?

• Has an invading army ever used a natural disaster as prelude to their invasion?

• a couple of brief examples in While we're all hoping for the best with Hurricane Sandy, what are some of the great natural disasters of history with which us lay-folk might not be familiar?

• one brief example in What natural disaster significantly changed the course of history?

portents may or may not be considered 'disasters'

• Why have almost all cultures in ancient history uniformly perceived comets as a sign of death, destruction and plague?

• "In this year terrible portents appeared in Northumbria... these were exceptional flashes of lightning, and fiery dragons were seen flying up in the air..." Is this account from the Anglo-Saxon chronicle a simple fabrication, or a misunderstanding of a natural phenomenon? and a bit more in How do historians account for presentism, bias and ideology in primary sources?

• How where eclipses (both Solar and Lunar) viewed and explained through history?

• a mention without further discussion in Comparing the Battle of Rorke's Drift with the battle of Battle of Isandlwana (which took place the same day), and I have a question.

man-made disasters during wartime

• Has there been cases where an army uses a body of water to flood another in the West? If not, why not?

edit: oh yeah, if you have follow-up questions on locked threads, ask them here & include the user's username so they'll be auto-notified