Costa Rica Receives on Average 1.100 Lightning Strikes Per Day
A report in today's issue of the Spanish language daily, La Nación, says that each day, on average, 1.100 lightning strikes hit the country and that the discharges are the cause of 70% of the electrical service failures and responsible for the death 15 people in the last two years.

Figures released by the Instituto Costarricense de Electricidad (ICE) and the Instituto Meteorológico Nacional (IMN) - the weatherman - reveal that in 2005 there were 436.000 discharges and this year there have been 384.000 discharges between January and the end of October.

Record keeping for the electrical discharges began in 2002 in an effort to determine the areas most affected and with the intent to avoid loss of life and damage to the electrical service network.

The joint report by the Sistema Nacional de Detección y Análisis de Descargas Atmosféricas (ICE-IMN), says that the electrical discharges can happen at any time, including the "dry" season (November to May).

An lightening bolt can reach a temperature of 30.000 Celsius (three times the outer layer of the sun) and generates enough energy to light up 1.000 homes.

The figures indicate that the months of May to October, the rainy season, has the highest level of electrical discharges, with July and September being the worst months.

Generally, the reports indicates, that lightning occurs between noon and 10:00pm. An analysis of the date collected shows that 6:00pm the peak.

The data also shows that the areas of the Pacific coast bestween Quepos and Puntarenas receives the largest number of discharges, followed by the Nicoya Peninsula (also on the Pacific coast); Los Cerros de Aguacate - between Atenas, San Mateo and orotina; and in areas of Alajuela, Heredia, San Ramón, Cuidad Quesada and San Carlos. Areas of Guanacaste, the northern region and south Pacific also receive a high number of discharges.

Lightning: How it is formed
The first process in the generation of lightning is still a matter of debate: one common idea from scientists is that lightning forms from the ejection of charged particles from the sun, which reach Earth through the solar wind.

These charged particles cause the Earth to acquire an electric charge in its outer atmospheric layers, especially the ionosphere.

Large quantities of ice in the clouds has also been scientifically proven to enhance lightning development.This charge will neutralize itself through any available path. This may assist in the forcible separation of positive and negative charge carriers within a cloud or air, and thus help in the formation of lightning.

Another theory is that opposite charges are driven apart by the above mechanism and energy is stored in the electric fields between them. Cloud electrification appears to require strong updrafts which carry water droplets upward, supercooling them to -10 to -20 C.

These collide with ice crystals to form a soft ice-water mixture called graupel. The collisions result in a slight positive charge being transferred to ice crystals, and a slight negative charge to the graupel. Updrafts drive lighter ice crystals upwards, causing the cloud top to accumulate increasing positive charge.

The heavier negatively charged graupel falls towards the middle and lower portions of the cloud, building up an increasing negative charge. Charge separation and accumulation continue until the electrical potential becomes sufficient to initiate lightning discharges.

When sufficient negative and positive charges gather, and when the electric field becomes sufficiently strong, an electrical discharge (the bolt of lightning) occurs within clouds or between clouds and the ground. During the strike, successive portions of air become conductive as the electrons and positive ions of air molecules are pulled away from each other and forced to flow in opposite directions.