:This article is about the atmospheric phenomenon. For other uses of the term thermal, see thermal (disambiguation). A thermal column (or thermal) is a column of rising air in the lower altitudes of the Earth's atmosphere. Thermals are created by the uneven heating of the Earth's surface from solar radiation, and an example of convection. The Sun warms the ground, which in turn warms the air directly above it. When a pool of warmer air accumulates, it expands and becomes lighter (less dense) tha… (More on Thermal)