Pelean and Plinian eruptions are the most dangerous and explosive of the eruption types. Pelean eruptions are named for the catastophic eruption on the island of Martinique in the Carribean Sea in 1902. The eruption and the pyroclastic flow that followed killed 29,000 people almost instantly. "Glowing clouds" of gas and ash flew down the mountain at over 70 miles per hour. The cloud was so full of ash that it was heavier than air and hugged the ground as it approached the coast. The temperatures were probably around 700 degress F. which would annihalate everything in its path.

The only person to survive was a prisoner that was sentenced to death. The only reason he survived was that he was imprisoned in a very thick walled cell and the only door faced away from the explosion.

A Plinian eruption is the most explosive of the eruption types. Mt. St. Helens eruption was a plinian eruption. Plinian eruptions are characterized by a very high ash cloud that rise upwards to 50,000 feet (almost 10 miles) high. Very deadly pyroclastic flows are also part of plinian eruptions.

Mt. Vesuvius, which erupted in 79 A.D. in Italy, was a classic Plinian eruption. Very hot ash falls killed thousands of people in the city of Pompei. Ash falls as high as 17 feet buried the city. Plinian eruptions were named for Pliny the Elder of Rome who died in one of the many eruptions of Vesuvius.

The photo on the left side of this card shows Mt. St. Helens in its plinian eruption on May 18, 1980. The ash cloud rose to a height of over 50,000 feet.

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