Severe Weather in Ethiopia

A tornado is formed when a rotating body of air, also known as a vortex tube, forms due to an increased wind speed due to altitude (vertical wind shear). This vortex tube is then lifted off of the ground by the thunderstorm’s updraft. Once the air mass is lifted nearly vertically, it is called a mesocyclone. Finally, the fully developed tornado descends from the lower part of the “wall cloud”.

In the United States, most tornados usually travel southwest to northeast or west to east. Tornados usually travel this path because there is a lot of moisture. These areas tend to be largely agricultural (unfortunately). The dryline also helps initiate tornadoes.

Tornadoes can happen in any country that meets the criteria for tornado formation. This includes having abundant low-level moisture, atmospheric instability, and a trigger i.e. a cold front, etc. that lifts the moist air aloft. That being said, Ethiopia can experience tornados as it is close to the eastern coastal area. However, they probably do not last very long as the terrain can be mountainous, especially the capital city. The average number of tornados observed in the US each year is over 1 thousand (http://www.ncdc.noaa.gov/climate-information/extreme-events/us-tornado-climatology). Unfortunately, I couldn’t find a website that provided any information on the average number of tornadoes that occur yearly in Ethiopia.

 

Source:  http://www.windows2universe.org/earth/Atmosphere/tornado/agri_map.html

At first, I didn’t know what to think when I saw that graph as it made sense to me that the number of tornadoes could’ve increased due to global warming, however after reading an article that I found online (http://notalotofpeopleknowthat.wordpress.com/2012/01/05/us-tornado-trendsupdated-to-2011/), it made perfect sense that the “increase” was due to the advancement in technology. Today’s technology makes it easier to monitor and count the number of tornado occurences.

There are three requirements for a hurricane to form. This includes a warm ocean temperature (needed for evaporation), a deep, warm ocean layer, and a coriolis (to initiate spinning). Hurricanes are called hurricanes in the Atlantic and East Pacific regions. It is called a cyclone in the areas of the Indian Ocean near Australia and a typhoon off the coast of China and Indonesia. In the United States, hurricanes travel the warm Gulf Stream and is steered by the west to east flow of the Westerlies and the Jet Stream. This is the dominant direction of hurricane travels because it has the requirements needed to form a hurricane. The Gulf of Mexico has the warm ocean temperature, deep, warm ocean layer, and the coriolis which is the dryline.

Source: http://www.learnnc.org/lp/editions/nchist-recent/6248

According to the hurricane map, hurricanes do not form in Ethiopia, however it is said that hurricane Sandy could have possibly started in the Ethiopian Highlands. In the U.S, there is an average of 5 hurricanes per every 3 years. That comes out to approximately 1.6 hurricanes every year (http://www.ussartf.org/hurricanes.htm). There are no hurricanes that hit Ethiopia (http://www.learnnc.org/lp/editions/nchist-recent/6248).