A number of structures in the Czech Republic were affected by flooding in August 2002. In particular, damage to structures adjacent to the Vltava River in Prague was on an unprecedented scale. This paper reports on a forensic investigation to assess whether the flooding was exceptional and to identify the main causes of structural failure. The work included statistical analysis of hydrological data dating back to 1827, from which it was shown the 2002 event had a considerably long return period. However, the investigation also revealed that lack of structural robustness may have contributed to disproportionate failure.