The level of activity at the Soufriere Hills during the night was considerably lower than that observed during the day on 11 August. It continues to be dominated by small- to medium-sized rockfalls from the flanks of the growing lava dome. A large rockfall at 01:30 this morning may have resulted in a small pyroclastic flow in the Tar River Valley. Several small hybrid earthquakes and a few episodes of low-amplitude low-frequency tremor were also recorded. Visibility during the early morning period was very poor, with the volcano obscured by low clouds.
People in areas affected by recent ashfalls should exercise great care when driving and should wear dust masks.
Dome growth at the Soufriere Hills volcano is still continuing and the current phase of activity has led to significantly increased hazards in some areas of the evacuated zone. In particular, we expect significant-sized pyroclastic flows to occur more frequently in the Tar River Valley area. These will obviously be associated with ash clouds which will be blown on the wind, with areas affected by ashfall being determined by the wind direction and strength at that time. The Tar River Valley and surrounding areas are now extremely hazardous, and should not be entered under any circumstances. If activity continues, there is a risk that flows or ash surges may come over Farrells Wall and the upper reaches of some of the ghauts closest to the Tar River Valley. People are, therefore, advised not to work these areas. We also urge individuals who continue to ignore this advice to think very seriously before making trips to these highly hazardous zones.