The most violent eruption in Guatemala in more than a century generated pyroclastic flows. Such flows can reach speeds of up to 450 miles (700km) per hour.
The eruption generated pyroclastic flows – torrents of superheated rock, ash, gas and volcanic matter – which tore down the slopes, engulfing villages such as El Rodeo and San Miguel Los Lotes.
Pyroclastic flows have been known to reach speeds of up to 450 miles/hr (700km/hr), with temperatures ranging from 400F to 1300F (200C to 700C).
The burning ash and mud left many victims unrecognizable.
The official death toll from the destruction at the Fuego volcano has risen to 69, with thousands of people in temporary shelters.
Ash from the eruption rose up to 10km (6 miles) into the sky.