Wiktionary
n. (context volcanology English) A dense flow of volcanic ash, dust, rocks and debris that cascades at high speed down the slope of a volcano during an eruption.
Wikipedia
A pyroclastic flow (also known scientifically as a pyroclastic density current) is a fast-moving current of hot gas and rock (collectively known as tephra), which reaches speeds moving away from a volcano of up to 700 km/h (450 mph). The gas can reach temperatures of about 1,000 °C (1,830 °F). Pyroclastic flows normally hug the ground and travel downhill, or spread laterally under gravity. Their speed depends upon the density of the current, the volcanic output rate, and the gradient of the slope. They are a common and devastating result of certain explosive volcanic eruptions.
Usage examples of "pyroclastic flow".
There are no Alpine peaks or grinding glaciers, no great deposits of oil or precious metals, not a hint of a pyroclastic flow.
In burning slabs like pyroclastic flow the top of the tower slewed off, militia pods falling out and tumbling.
He could see what looked like a pyroclastic flow, a heavier-than-air mix of gases and hot volcanic fragments.
Even if the pyroclastic flow is minimal, Landing will soon be covered with ash at the rate it's now falling.
Even if the pyroclastic flow is minimal, Landing will soon be covered with ash at the rate it´.
Even if the pyroclastic flow is minimal, Landing will soon be covered with ash at the rate it’.
Even if the pyroclastic flow is minimal, Landing will soon be covered with ash at the rate its now falling.
An enormous quantity of glowing magma was purged in a pyroclastic flow, a tumultuous compound of incandescent rock fragments and heated gas that travels over the ground like liquid molasses but at velocities exceeding 160 kilometers per hour.
No one living in Herculaneum would need to worry about the slow-moving pyroclastic flow of molten pumice and mud which would eventually engulf the city and bury it beneath sixty feet of solid rock.
Then the men aboard saw a pyroclastic flow, a terrible avalanche of glowing hot dust and ashes rushing down the mountainside toward the bay, the forest on both sides bursting into flame from its heat.
The pyroclastic flow had lost considerable of its force and coherence before it reached the fleet, but even so, some of the upright ships burst into flame.
Not Mama, who just snorted that people who built in the path of pyroclastic flow must eat ashes and like it, and with all the old lava about, one could not mistake where that was likely to be.
In a volcanic eruption, the same thing happens with a pyroclastic flow.
Side openings occurred, and the red rock flowed from them like a steaming avalanche, occasionally breaking loose whole sides of the mountain in a semiliquid, fiery hot gel called pyroclastic flow.