I've never seen any disasters in EB, although that may be because I've only played beyond 240 with Bactria. I do wonder though why you would want to script historical storms, floods or plagues, given your attitude towards historical determinism in the rest of the mod (e.g. not wanting to script the emergence of Hannibal). I can understand scripting volcanic eruptions and earthquakes, given that they build up over such a long period that I'd expect they'd probably happen again if the period covered by EB was run again, but weather is chaotic and unpredictable even in the short term, and plagues are directly affected by the movements of carriers, among other things. It seems highly doubtful that a historical storm, flood or plague would always happen at a specific time and place.