How fast did the lava flow in Mt. How fast did the lava flow in Mt. Timmy Hi Timmy, The lava at Mt. Pelee is very very viscous and barely flows at all. However, Mt. Pelee if famous for producing a very different type of volcanic product - a pyroclastic flow.
Pyroclastic flows are mixtures of hot gas, ash, and dust.
It was a pyroclastic flow that killed all those folks in St. Pierre back in 1902.