In the late summer or autumn of 79 AD, Mount Vesuvius violently spewed forth a deadly cloud of super-heated tephra and gases to a height of , ejecting molten rock, pulverized pumice and hot ash at 1.5 million tons per second, ultimately releasing 100,000 times the thermal energy of the atomic bombings of Hiroshima and Nagasaki. The event gives its name to the Vesuvian type of volcanic eruption, characterised by eruption columns of hot gases and ash exploding into the stratosphere, although the event also included pyroclastic flows associated with Pelean eruptions.