BRADES, Montserrat (CMC):

Residents were evacuated from the southernmost part of the occupied safe zone of this British Overseas Territory after the lava dome of the Soufriere Hills Volcano collapsed shortly before midnight sending ash more than 40,000 feet above sea level.

A brief statement issued by the Montserrat Volcano Observatory (MVO) said there had been "a partial dome collapse on the west side of the Soufriere Hills Volcano" shortly before 11:27 pm local time on Monday without any precursory activity.

"Part of the western side of the lava dome collapsed generating pyroclastic flows - a combination of hot gas, ash and rocks - that reached Plymouth and the sea.," the MVO said adding that there were also a "few explosions from the dome during the collapse, with the largest at approximately 11:32 pm.

"The height of the ash column was estimated at 12 kilometres (40,000 feet) above sea level.