Meteorologists are not entirely sure what causes the somewhat rare weather event called a heat burst, but anyone who has experienced one can tell you they are quite bizarre. In most cases, the air temperature can increase 20°F or more in a matter of minutes, causing ferocious and damaging winds. What’s even more bizarre is that they almost always occur late at night or in the very early morning hours, which usually catches people by surprise.

While the cause of a heat burst isn’t fully understood, it’s believed that a specific set of weather events must all be in place at the right moment. To begin with, the rain from a decaying thunderstorm must fall through a layer of very dry air. This in itself is uncommon, because in order to make thunderstorms, there needs to be moisture. Second, as the rain falls through the drier air, it evaporates and rapidly cools. This creates a pocket of very dense cool air that is much heavier than its surroundings. Because the air is heavier than it’s surroundings, it rapidly descends. As the air descends, it compresses, thus causing it to warm and at the same time gains downward momentum. This momentum causes it to overshoot its atmospheric equilibrium which further increases compression and warming. If the descending air has enough momentum, it will crash into the ground spreading out like a pancake. Those nearby will feel a substantial increase in temperature and a decrease in humidity until the atmosphere stabilizes, which can take up to an hour.

So, not only does the rain have to pass through a very dry layer of air, it must evaporate fast enough, sink fast enough, and have enough momentum to reach the ground. Because the sinking air descends very rapidly, very strong winds usually accompany a heat burst. It’s not uncommon for the wind speed to exceed 60 mph or more, similar to a microburst. This often times can tear shingles from rooftops and knock down trees.

One of the more recent heat bursts occurred in Wichita, Kansas in the middle of June 2011 just after midnight. Here’s a couple video clips of the local news stations reporting on the event.



So just how warm can it get? Very warm. In fact, down right hot and very windy! And while these events are uncommon, they are not that rare. In fact, in the United States we typically see about one a year during the warm summer months. Here are some other examples of heat bursts that have occurred over the years:

  • Cozad, Nebraska, June 26, 2008: Wind gusts reached 75 miles per hour, as the temperature rose 20 °F (11 °C) in a matter of minutes.
  • Midland, Texas, June 16, 2008: At 11:25 pm a wind gust of 62 mph occurred as the temperature rose from 71°F to 97°F in just a few minutes.
  • Emporia, Kansas, 25 May 2008: Reported temperature jumped from 71°F to 91°F between 4:44 am and 5:11 am (CDT) as the result of wind activity from a slow moving thunderstorm about 40 miles to the southwest.
  • Oklahoma, May 22–May 23, 1996: The temperature in the towns of Chickasha rose from 87.6 °F to 101.9 °F in just 25 minutes, while the temperature at Ninnekah rose from 87.9 °F to 101.4 °F in 40 minutes. In addition, wind damage was reported as winds gusted to 95 mph in Lawton, 67 mph in Ninnekah, and 63 mph in Chickasha.
  • Kopperl, Texas, 1960: A heat burst sent the air temperature to near 140 71°F, supposedly causing cotton crops to become desiccated and drying out vegetation (undocumented).
  • Cherokee, Oklahoma, 11 July 1909: at 3:00 in the morning, a heat burst south of Cherokee, Oklahoma reportedly caused the temperature to rise briefly to 136°F, desiccating crops in the area.