What do we call a cloud formed from the gases in magma?

A cloud formed from the gases in magma is referred to as an ash cloud. When volcanic eruptions occur, the intense heat and pressure cause the magma to release various gases, including water vapor, carbon dioxide, sulfur dioxide, and other volcanic gases. These gases can combine with ash and other particulate matter ejected during an eruption to form clouds that can rise high into the atmosphere.

Ash clouds are significant because they can impact air travel, reduce air quality, and affect weather patterns. They distinguish themselves from other types of clouds, as their composition directly relates to volcanic activity.

The other options relate to different phenomena; for example, a smoke cloud typically results from combustion processes, while a vapor cloud usually refers to water vapor. A gas cloud might suggest a more general grouping of gases without the specific implications of volcanic activity. Thus, the choice of 'ash cloud' accurately captures the unique characteristics of clouds associated with magma gases.