There was serious pyroclastic flow activity on the northern side of the volcano this afternoon, with pyroclastic flows in Mosquito Ghaut, Paradise River, Farms River almost to the sea beside WH Bramble Airport.
An intense swarm of hybrid earthquakes began at 11 am, and rapidly escalated to repetitive events which merged into continuous tremor after 12:15 pm. At about 1 pm major pyroclastic flow activity began in Mosquito Ghaut, which generated an ash cloud to over 30,000 ft within minutes. The flow travelled into Farms River to Trants Bridge. Down river of Bramble the flows fanned out into Bethel and Spanish Point almost to the sea. On the northern side Farms and Trants villages were affected, and the surge reached to Trants bridge. A total of at least 2 square kilometers of land was covered by the pyroclastic flow and surge.
The lower half of Harris village village was also impacted, and an ash surge travelled from the Farrell's area down to the west at least as far as Dyers, and into the upper reaches of Dyer's Ghaut. There was no activity in the Gages valley during the afternoon.
The seismic activity had declined by 3 pm, and the volcano has been quiet since that time, with a few rockfalls and hybrid earthquakes.
This afternoon's pyroclastic flows followed a period of escalating activity during the previous 24 hours, with three periods of intense earthquake activity which merged into volcanic tremor, and were accompanied by rythmic inflation and deflation of the mountain detected by the tiltmeter on Chances Peak. Since the end of the activity this afternoon, the tiltmeter has shown signs of inflation again, and further activity could occur within a few hours.
This makes the entire central corridor and the eastern side of the volcano very dangerous, and people should not enter the area. Rescue missions will be carried out by professional teams with helicopter support. The airport was successfully evacuated before the pyroclastic activity this afternoon, and remains closed at this time.