The gigantic plume of smoke from the volcano dominates the skyline
Pyroclastic flows are also called nuees ardentes - or "burning clouds" - and are probably the single most destructive weapon in nature's armoury, capable of flattening cities in seconds.
It was such a catastrophe that destroyed the Roman town of Pompeii in AD79.
The 3,300 ft Chaiten Volcano, 800 miles south of the Chilean capital Santiago, is erupting for the first time in thousands of years, sending a plume of ash into the sky that stretches as far as Argentina.
It is also spewing out chunks of lava and hot rock. Authorities have already evacuated Read more: