For several weeks now Soufriere Hills volcano, erupting since July, 1995 has been spewing ash high in the sky and pelting pyroclastic flows down its western flanks. All this time it has been boiling to explosive stages, catching a wind shift on at least one occasion when there was an eruptive event on "the night of Monday 28th July 2008 which generated a large ash column, pyroclastic flows and falls of airborne pumice in some inhabited areas," as reported by the Montserrat Volcano Observatory (MVO).
The MVO following that for the most part reported activity at the Soufriere Hills to be at a low level until December 2, 2009, they reported: "There was an explosion and pyroclastic flow at the Soufriere Hills Volcano at approximately 9:35 p.m. local time…" The pyroclastic flow was on the western flank of the volcano. It travelled down Gages Valley and into Plymouth and appears to have reached the sea. Buildings were set alight in Plymouth and could be seen burning from Salem for several hours afterwards, according to the MVO report, but later reports modified some of the information."The not to long ago new level hazard at that remained at level 3. Since then the reports indicated that different factors caused the activity to have increased and so by December 26, "The Hazard Level is 4 with access to Area B restricted to residents only.
The "Level was increased from 3 to 4 by the NDPRAC on Monday 22 December due to the repeated occurrences of pyroclastic flows in the lower part of Tyers Ghaut," the MVO reported.As the flows and the ash clouds continued almost non-stop, the wind began shifting slowly northwards and by the morning of December 31, as the first festival jump up began winding up, moving towards the Salem Centre, all eyes began turning to the skies and the dark clouds of the continuing ash clouds which began sifting slowly the lightest of ash. There was a slight reprieve and a let up for New Years, but the warning had been given, the wind change was coming and by this time the MVO was getting ready to report, "the Soufrière Hills Volcano increased significantly during the past week with lava extrusion on the top, north, west and south-west side of the dome, as well as further ash venting at the top of the dome and pyroclastic flows down on Chances Peak’s side, Plymouth and in Tyers Ghaut."
"…the unfavorable wind direction, ash fall was reported over the week at Isles Bay, Garibaldi Hill, Old Towne, Salem and Olveston. Lava extrusion continues and widespread incandescence was visible on the dome at night whenever the weather was favorable. Large incandescent blocks, deposited by rockfalls and pyroclastic flows, were visible at several occasions at night in the lower parts of Tyers Ghaut, as were fires triggered by surges in the neighboring valley."
This triggered concern from the National Disaster Preparedness Response and Advisory Committee (NDPRAC) who issued a press release today, January 2, 2009, which states in part: "The MVO has observed a significant change in the pattern of activity. A regular cycle of strong volcanic pulses has become established resulting in larger and more energetic extrusion of magma. The number of pyroclastic flows on the north and North West side of the mountain has increased and is filling Tyre’s Ghaut. This has enabled flows to jump over the wall of the ghaut and reduces the distance to the Belham River Valley."