The eruption began with the mountain roaring from the inside. Residents say it was hard to sleep during the night. A large eruption began at dawn on December 16th, 1631. A Plinian column erupted up to 28 kilometers high along with tephra fallout for a couple hours. The flowing ash sped downward along the main valleys, destroying all vegetation and buildings and killing all living organisms in its way. On December 17th, there was a decrease in the strength of the activity. After the main phase was over, between 3,000 and 6,000 people were dead. Rescue teams arrived and saved thousands of survivors on December 19th.
Mt.Vesuvius is classified as a stratovolcano, because its eruptions normally involve huge explosions.