Catatumbo lightning is an atmospheric phenomenon in Venezuela. It occurs only over the mouth of the Catatumbo River where it empties into Lake Maracaibo.
It originates from a mass of storm clouds over nearby mountains, and occurs during 140 to 160 nights a year, 10 hours per day and up to 280 times per hour. It occurs over and around Lake Maracaibo, typically over the bog area formed where the Catatumbo River flows into the lake.
Catatumbo lightning changes its frequency throughout the year, and it is different from year to year. For example, it ceased from January to March 2010, apparently due to drought, temporarily raising fears that it might have been extinguished permanently.
Catatumbo lightning usually develops between the coordinates 8°30′N 71°0′W and 9°45′N 73°0′W. As the sun goes down, easterly winds begin to pick up speed. This is the development of a nocturnal low-level jet (NLLJ) similar to what we see in the Great Plains in North America. These winds bring moisture primarily from the Caribbean (some from the lake itself). This moist air flow hits the high mountain ridges of the Andes, the Perijá Mountains (3,750 m), and Mérida's Cordillera, which enclose the plain from three sides. The air is lifted and convection (thunderstorms) form over the mountains. As the NLLJ continues through the night, more thunderstorms are produced as others dissipate over the same area. This is known as terrain anchored convection. When the NLLJ weakens in the morning, thunderstorm development will cease. This pattern is repeated every night for much of the year.
The phenomenon is characterized by almost continuous lightning, mostly within the clouds, which is produced in a large vertical development of clouds. The Lake Maracaibo Basin in North Western Venezuela has the highest annual lightning rate of any place in the world. The lightning produces a great quantity of ozone.
Impact on aviation
Apart from the impact on en-route traffic in the area, certain local airports, including Miguel Urdaneta Fernández Airport can be affected by the storms associated with Catatumbo lightning.