The ascending, vertical part of the mass of erupting debris and volcanic gas that rises directly above a volcanic vent. Higher in the atmosphere, columns usually spread laterally into plumes or umbrella clouds.

A cloud of tephra and gases that forms downwind of an erupting volcano is called an eruption cloud. The vertical pillar of tephra and gases rising directly above a vent is an eruption column. Eruption clouds may drift for thousands of kilometers downwind and often become increasingly spread out over a larger area with increasing distance from an erupting vent (note fan-shaped eruption cloud in photographs at left). Large eruption clouds can encircle the Earth within days.

Eruption cloud is often used interchangeably with plume or ash cloud.

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