The eruption from Mount Pelee was a pyroclastic flow. Pyroclastic flows are a mixture of solid pieces of hot, expanding gases that flows down the flank of a volcanic. This eruption is heavier-than-air and moves like a snow avalanche, except that it is very hot, contains toxic gases, and moves at hurricane-like speeds, over 100 km/hour. The type of flow that hit Saint Pierre was a Nuee Ardentes. These contain dense lava fragments from the collapse of a growing lava dome or dome flow. Saint Pierrre had about 30,000 people living in it in 1902. The pyroclastic flowed through the valley and into Saint Pierre. Within minutes, Saint Pierre was destroyed. It was so hot that iron melted easily like a broom next to a fire.
Posted by Josh