For those who are not aware, this is in Rabaul in Papua New Guinea. Since it destroyed the town back in the 1990s, the volcano has been rumbling consistently. When we were there six years ago, you could hear the explosions over 20 kilometres away when underwater.
I have never before seen video of a pyroclastic flow. Amazing. Just as the cloud of the eruption boils up, you can see the gray pyroclastic flow race down the slope to the water. (about 13 sec in) This hot gas and rock can travel 450mph and exceed 1800 degrees F. The only good thing about being in one is that you die quickly and don't suffer much.