The Taum Sauk reservoir is about 100 mile equidistant from St. Louis to the northeast, the New Madrid Fault to the southeast (where a 1.9 quake hit about five hours before the collapse) and Bagnell Dam/Lake of the Ozarks from where it the plant was monitored.
Follow the Taum Sauk developments at
Take a tour of the disaster with a Google Earth KMZ file.
You of course need to have Google Earth installed (free) and have a high bandwidth internet connection. The tour is more dramatic if you play with the horizon angle button and also set the terrain exaggeration to 3 (tools/options/evalation exaggeration)