Tornadoes near the equator?

[scott r currens]

I came across this article with pictures of a tornado in Barranquilha, Colombia. That city is only 10 degrees north of the equator. I hear reports of tornadoes in equatorial regions but this is the first time I have see an image of one.

http://www.metsul.com/secoes/visualiza.php?cod_subsecao=28&cod_texto=277

 

[Saul Trabal]

Interesting stuff, and nice photo. I seem to remember hearing on NPR (National Public Radio) that the most violent thunderstorms are in South America-I believe Argentina was the country mentioned.

Edited to add: I was right. Here's the link.

 

[Tarmo Tanilsoo]

Whoa... And it made big headlines... Nice photo and newspaper. However, I needed to use Babelfish to read that page since I don't speak Portuguese.

 

[B Ozanne]

Interesting stuff, and nice photo. I seem to remember hearing on NPR (National Public Radio) that the most violent thunderstorms are in South America-I believe Argentina was the country mentioned.

Edited to add: I was right. Here's the link.

Yes, the plains in Argentina have a very similar setup to the American Plains. But they are fairly far from the Equator, more than 20 degrees south.

 

[jladue]

Interesting stuff, and nice photo. I seem to remember hearing on NPR (National Public Radio) that the most violent thunderstorms are in South America-I believe Argentina was the country mentioned.

Here's the article where Zipser et al. describe how they defined "most violent storms". They defined intense updraft using proxies such as total lightning rate, the maximum height of strong (>40 dBZ) reflectivities, and the minimum brightness temperature in the 37 and 85 GHz microwave band. The latter is very sensitive to the amount of hail in the upper reaches of a thunderstorm. The Pampas region is very similar to the Great Plains in the US, basically an equatorward source of moisture east of a north-south mountain range. The westerlies down in Argentina do not retreat poleward as much in their summer as they do in the US summer so the area of intense storms is smaller but more concentrated. I'm sure the tornado frequency is high but nobody knows how high.

Speaking of tropical tornadoes, I suspect there are also many more than we currently know about just because there are more instances of thunderstorms in the more active regions than we see in the midlatitudes. Take a look at Zipser's paper and you see how active the African Sahel region can be for intense updrafts. I wouldn't be surprised to hear about some interesting tornado examples from tropical Africa.

The caution about Zipser's paper is that they're concentrating on updraft intensity near the anvil level. Tornadoes love to occur when there's intense updraft in the lowest 3 km. There's plenty of examples of storms with strong lower level updrafts and weak upper level updrafts.