Severe Weather in Costa Rica

    There are three steps that need to occur in order for a tornado to form. The first formation is  the vortex tube, which is a rotating body of air that starts on the ground. The vortex tube occurs because of vertical wind sheer. Next, the air, which is rotating horizontally, is then lifted off the ground by the updrafts from a thunderstorm. Once the rotating air mass is lifted almost vertically, the formation is considered a mesocyclone. The mesocyclone fully develops in the updraft of a thunderstorm; the tornado then descends from the rotating wall cloud in the lower part of the cloud (Griswold, lecture 19).

    In the United States, tornadoes typically travel from southwest to northeast.(erh.noaa) This movement is due to the "certain tornado-producing weather patterns." An example of this would be "hurricanes in South Texas or northwest-flow weather systems in the upper midwest" (web apps). The average number of tornadoes observed in the United States per year is about 1253 (ncdc.noaa). Tornadoes do not typically happen in Costa Rica(serendepityadventures) because "the weather does not get pushed along by frontal systems, like the Jet Stream or hurricanes" (insidecostarica). On June 5, 2013, a tornado hit Costa Rica, which was a rare occurrence. Within 30 minutes, the tornado tore through the town of Calle Valverde in Naranjo de Alajuela, causing damage. There were no life-threatening injuries, but at least 15 homes reported damage because of the tornado (insidecostarica.com).

Using the above map, Costa Rica is located to the south Nicaragua, Honduras and El Salvador, which only had 3-5 tornadoes in the years between 2000-2008. Costa Rica is shaded in grey, meaning they have no tornado occurrences. 

    Over the years, tornado occurrences have appeared to increase. I do not believe that tornado occurrences have actually increased, but I do, however, believe that technology advancements have allowed researchers and data collectors to observe and keep track of more tornado occurrences.

    There are three main requirements for hurricane formation. The first is warm ocean temperatures. This is necessary for the formation of hurricanes because a lot of evaporation is required. Next, deep warm ocean layer in depth is required so that when the winds churn up the water, the water will remain warm. Lastly, coriolis is needed to initiate the spinning (Griswold, lecture 20). 

    There are three terminologies for hurricanes, depending on where in the world they occur. Hurricanes occur in the Atlantic and East Pacific. Cyclones occur in the Indian Ocean near Australia. Last, Typhoons occur along the coast of China and Indonesia.

In the United States, the general path of hurricanes is the same as the path of tornadoes, as mentioned previously; southwest to northeast. The trade winds carry the hurricane while over water and are moved via the westerlies once at a higher latitude. (map)

     Hurricanes rarely happen in Costa Rica (aoml.noaa) because of it's location. When a hurricane is nearby, Costa Rica may experience an increase in rainfall, but a direct hit from a hurricane is rare (costarica.com).