One last earthquake turned the sleeping huge loose,
and soon 230 sq. mi. of green forest was entombed in a lunar wasteland. On May 18,
1980, U.S. Geological review volcanologist David Johnston had a clear view of
Mount St. Helens’s north side from his monitoring station 5.5 miles away. Just
seconds after the 30-year-old radioed his final words to colleagues, the
snow-capped volcano blew itself enormously apart.
The mountain had been calm until two months earlier, when a quake jolted the resting giant to life. With no a cap of earth to keep it sealed under pressure, Mount St. Helens exploded. Sulfur dioxide gas in the recently exposed magma, together with compressed water and steam, extended and blew out the north side of the mount. This lateral blast of ash, magma, rocks and sand reached 100 stories high and spread 10 miles extensive as it plowed down valleys and over ridges at speeds near 700 mph.
It was this lateral blast, or surge, as some
geologists prefer to call it, which claimed most of the 57 fatalities that day with
Johnston. Neither he nor his trailer was ever found, both presumably hurtled
into the next vale and buried in wreckage.
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