In a manner similar to what happens when a Santa Ana wind rushes down into the low coastal areas of southern California, a heat burst raises temperatures by compressing air. Usually associated with thunderstorms, heat bursts typically occur during the night when turbulent air from as high up as 20,000 feet is forced downward as a storm begins to break up and dissipate. Meteorologists theorize that this happens when virga (rain that evaporates before reaching the ground) is present in dry, cold air. The resulting denser air is pulled down by gravity, increasing air compression near the ground rapidly and causing temperatures to rise unexpectedly.

In Waco, Texas, on June 15, 1960, it was reported that a heat burst caused the temperature to soar to 140°F (60°C) for a brief period that was accompanied by winds of about 80 miles (129 kilometers) per hour. More recently, in May of 1996, temperatures rose from about 88°F (31°C) to 101°F (39°C) in the towns of Chickasha and Ninnekah in about 30 to 40 minutes; and on August 3, 2008, Sioux Falls, South Dakota, saw the temperature shoot up from about 72°F (22°C) to 101°F (39°C) during gusting winds of 50 to 60 miles (80 to 100 kilometers) per hour. Perhaps most remarkable was a heat burst during the recent heat wave and fires in Australia. On January 29, 2009, at 3:00 A.M., a heat burst maxed out thermometers at 107°F (41.7°C).