Pyroclastic flows can reach up to 700 km/h (450 mph)
Deriving from the Greek pyr (“fire”) and klastos (“broken in pieces”), pyroclastic flows are clouds of gas and volcanic matter that spread across the ground after a volcanic eruption. They can even cross large bodies of water, and can reach temperatures of 1,000 °C (1,830 °F).
A pyroclastic flow would not suffocate you, because you would be incinerated before there was time to breathe.
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