Katabatic winds and Casper the friendly Ghost

A katabatic wind, from the Greek word Katabatikos meaning “going downhill” is the technical name for a wind that forms when a cold dense mass of air slides down a mountain or hillside. Katabatic winds can be found all over the world, one of the most famous is the Mistral which blows down the Rhone Valley in southern France. It can become very strong reaching speeds of 80 miles per hour. The katabatic wind that affects Ascension Island isn’t that strong. It is caused by the air over Green Mountain cooling faster than that across lower lying areas of the island. The air then flows from the cooler Green Mountain down to Two Boats, Travelllers Hill and eventually reaching Georgetown. As this wind form in the early part of the evening Two Boats often has a short period of very strong gusty winds, which then calm down as the temperature difference between the two places equal out. Some people liken the reducing of the temperature caused by a cool katabatic wind to the nearby presence of a ghost. Residents of Travellers Hill should beware, a cool evening breeze could be a katabatic wind, or it could be Casper out for fat busting evening stroll.