A small but highly fluidized pyroclastic flow traveled down
the narrow Belham stream channel as far as 5 to 6 km from a lava dome
growing at the summit of Soufriere Hills volcano in Montserrat. The
basal part of the pyroclastic flow was confined to the channel bottom,
but the overriding hot ash cloud burned and killed vegetation along the
channel. The pyroclastic flow was triggered by a partial collapse of
the dome. With initial temperatures higher than 900°C, the rock
debris and gas carried by a pyroclastic flow or surge easily remain hot
enough to burn or singe combustible material even when they travel more
than 20 km from a vent. |