During the night two large events took place. The first is the deadly collapse with a following pyroclastic flow that struck at Sinabung; the second is the powerful eruption that started at Tungurahua.
In a decision that I guess will be hotly debated for some time the Indonesian mitigation authority decided to lower their risk assessment for the volcano and letting people back into the 7km exclusion zone due to the diminished activity at the volcano. In the end they settled for a 5 km exclusion zone, and it is rumored that not even that distance was upheld in places.
During the last couple of weeks an 800 meter long lobe of brittle and very slow moving magma had formed down the valley that the pyroclastic flows has followed so far. This meant that the pyroclastic flows started from a lower point and thusly had less power and travelled a shorter distance. This probably fooled the volcanologists on site.
It is said that hindsight is 20/20, but having an 800 meter long lobe of brittle magma hanging down a mountain should really have raised concern. For whatever reason it did not do that.
During the European night the lobe failed catastrophically and came rushing down in the largest pyroclastic flow to date. So far 14 deaths have been confirmed, but the risk is great that the number will increase in the days to come.
I will leave this tragedy with one wish, that in the future dialing back on volcanoes will be done in a slower fashion to ensure that the volcano is really on the way to stop erupting. Today was unnecessary.
While people had just begun to grasp what had happened at Sinabung the next blow came as Tungurahua started a large eruptive episode. It quickly became clear that the eruption had caused an eruptive column that was between 10 000 and 15 000 meters high.
The 5 023 meters high Tungurahua in the Cordilleras has been more or less constantly erupting since August 1999. It is a medium-powerful strato-volcano capable of eruptions ranging from VEI-1 up all the way to VEI-5 from a historical standpoint.
Current Tungurahua (T3) formed in a VEI-5 eruption 3 000 years ago with a horse shoe shaped caldera formation. T1 was most likely destroyed in an even larger VEI-6 eruption. There is nothing pointing towards this growing into something like that.
Judging from the columnal height and probable ejection rate this looks to be another VEI-3 eruption and that is normal for this particular volcano. The biggest worry is the town of Baños de Agua Santa that resides just 8 kilometers from the volcano. There are also close by villages in danger.
The greatest dangers are pyroclastic flows running down the slopes and Lahars forming from the glacier at the top. No deaths have been confirmed as of now.
The eruption is said to have been precluded by small explosions on the 30th ejecting coarse black sand. But, that is not that uncommon from a volcano that has almost constantly been erupting for 15 years.