Saharan Air Layer Passes Over Costa Rica Today
A continent-sized cloud of hot air and dust originating from the Sahara Desert crossed the Atlantic Ocean, headed towards Florida and the Caribbean, should hit Costa Rica possibly today, according to the Instituto Instituto Meteorológico Nacional (IMN).

The dust cloud had been expected to have reached Costa Rica last Friday.

Gustavo Murillo, of the IMN, says that the cloud full of contaminants, spores and micro organisms, is travelling slower than had been expected.

Guillermo Quiros, oceanographer and director of the Instituto de Costas assures that the effects of the cloud are already here.

A Saharan Air Layer, or SAL, forms when dry air and dust rise from Africa's west coast and ride the trade winds above the Atlantic Ocean.

These dust clouds are not uncommon, especially during the months of July and August. They start when weather patterns called tropical waves pick up dust from the desert in North Africa, carry it a couple of miles into the atmosphere and drift westward.

The SAL is a subject of ongoing study and research.