There is a very wide range of hazards and disasters we must consider when planning GIS solutions for Emergency Management. It is easy to focus on the very large and obvious events - things like hurricances, earthquakes, and disease epidemics. For many GIS managers, however, there are day-to-day emergency situations on a local level that deserve plenty of attention: house fires, auto accidents, and violent crimes - just to name a few.
The Federal Emergency Management Agency (FEMA) keeps a running tab of declared disaster events [1] in the US. You've probably heard before on the news when the President declares one place or another as a "Federal Disaster Area" - and FEMA now publishes quite a few interesting summary maps of recent disasters at their GeoPlatform [2].
Take a look at this interactive summary of the 2014 Mississippi Tornado Outbreak [3].
A complimentary example can be found on a map mashup developed in Hungary to provide information on a wide range of hazards and disasters around the world. Take a look at this application called AlertMap [4].
Links
[1] http://www.fema.gov/disasters
[2] http://fema.maps.arcgis.com/home/
[3] http://www.esri.com/services/disaster-response/severe-weather/MS-tornado-local-impact-map
[4] http://hisz.rsoe.hu/alertmap/index2.php