Eruption of the Soufriere Hills volcano began on 18 July 1995 after three years of elevated seismic activity. Four months of increasingly vigorous phreatic activity culminated in mid-November 1995 with the initiation of dome growth. Growth rates increased unevenly through early March 1996, with fluctuations on time-scales from hours to months. Since March 1996, gravitational collapse of the unstable dome flank has affected an ever-increasing area with pyroclastic flows, surges and ashfalls. Major collapse of the eastern flank on 17 September 1996 resulted in a sub-Plinian explosive eruption later that day. By February 1997, the dome had outgrown the confines of the crater and begun to spill into the surrounding valleys. A large collapse on 25 June 1997 caused pyroclastic flows and surges on the northern flanks and resulted in the only deaths of the eruption. In August, September and October 1997, vulcanian explosions followed further collapses on the western and northern flanks. The largest event of the eruption occurred on 26 December 1997 with failure of the southwestern flank of the volcano producing a debris avalanche and large dome-collapse pyroclastic flows. Dome growth ceased in early March 1998, but residual volcanic activity has continued and consists of ash venting, mild explosions and dome-collapse pyroclastic flows.