Last night Cape Town was buffeted by a cold front bringing torrential rain and gale-force winds. The build up to this cold front, and the subsequent weather, is a classic case study of Cape Town’s winter weather. Firstly a stream of high cirrus clouds rolled in, creating spectacular clouds, but definitely warning us of an impending storm. This was followed by a strong and destructive north-westerly wind, as heavy clouds built up over Table Mountain. The cold front would have been felt in Camps Bay, but it was Newlands that felt the full force of this storm.
Located on the leeward side of the mountain, traditionally the dry side of a mountain range, Newlands carries the surprising title of South Africa’s wettest suburb. You may well question why this is so.
The general rule-of-thumb is that higher levels of rain fall on the side of the mountain facing the prevailing wind, but Table Mountain breaks this rule resulting in a very wet Newlands area. The eastern, leeward side of the mountain, where Newlands is based, can see up to 2000 millimetres of rainfall per annum. Camps Bay sits on the windward side of the mountain, traditionally the wet side of a mountain range, but receives less than 600 millimetres of rainfall per annum. The reason for this strange phenomenon is that Table Mountain is not high enough to prevent the north-westerly winds from passing over the mountain range. This causes sodden air to rise up and over the summit, which condenses on the leeward side of the mountain and results in high rainfall patterns on the eastern-slopes during the winter months. Wind rushing over the edge of the mountain also causes classic winter storm turbulence, manifested by intense and blustering gales that can tear roofs off houses and uproot trees.
Next time you see high level cirrus clouds rushing in, and feel the north-westerly winds picking up, batten down the hatches, especially if you are in Newlands, and prepare for a typical Cape Town storm.