In addition, if the cavalry could catch an infantry unit before it formed square properly, the horsemen could usually inflict severe casualties or even destroy the unit completely. The Battle of Quatre Bras (1815) saw several examples, with several British units being surprised at close range by French cavalry hidden by the terrain. Other circumstances that could lead to a successful cavalry attack included sudden rainstorms soaking the infantry's gunpowder, effectively reducing their weapons to very short pikes, or a mortally wounded horse in full gallop crashing into the square, opening a gap that could be exploited, as happened at the Battle of Garcia Hernandez, shortly after the Battle of Salamanca (1812).