AUSTIN (KXAN) — The first freezing cold mornings of fall bring unique sights if you pay close enough attention, from frost on blades of grass to rising clouds of water vapor illustrating evaporating heat from the surface of the Highland Lakes.
Tuesday morning, the Executive Director of the Lady Bird Johnson Wildflower Center Patrick Newman captured warm, moist air rising from one of many karst features on the Center’s property in south Austin.
According to the National Parks Service, karst is a type of landscape where the dissolving of the bedrock has created sinkholes, sinking streams, caves and springs. Karst is associated with soluble rock types including limestone, which is common in central Texas. A typical karst landscape forms when much of the water falling on the surface interacts with and enters the subsurface through cracks, fractures, and holes that have been dissolved into the bedrock. After traveling underground, sometimes for long distances, this water is then discharged from springs, many of which are cave entrances.
It appears that the air in the underground karst feature, kept warm by the insulating earth and soil and moistened by underground water, was rising out of the entrance to the feature as a visible cloud. This is similar to how we can “see our breath” on cold mornings.
As Mr. Newman more eloquently put it, “the land was giving a prolonged exhale after having survived another summer.”