A sharp view of La Palma warns of a change in the weather

Clear visibility from Tenerife to La Palma? Then you really should wrap up warm. In the Canary Islands, such a moment is seen as a warning sign, and there are sound meteorological reasons for this.

It is usually caused by a shift in the large-scale airflow. The trade winds weaken, the wind veers slightly west or south-west, and at higher altitudes, drier air breaks up the stable atmospheric layering. It is precisely this interplay that makes the visibility from Tenerife across to the neighbouring island unusually clear.

Normally, a stable cloud cover hangs over the Orotava valley; here in the Canary Islands, this is known as ‚panza de burro‘, which translates as ‚donkey’s belly‘. Such clouds are a sign that the trade winds are blowing effectively. Incidentally, they also ensure that the grapes on the north coast ripen slowly and develop their full aroma, which gives the wine its characteristic style.

A clear view of La Palma is regarded as a warning sign on Tenerife

This stability is caused by what is known as an inversion. In this situation, warm air lies above and cooler air below, so that moisture is trapped as if under a lid and the clouds remain stationary.

If, on the other hand, La Palma appears crystal clear, it is precisely this cloud cover that is missing. The inversion, which normally lies like a lid over the north side, has dissipated. The air then appears clearer, but it is precisely this clarity that reveals that the trade winds have weakened and the atmosphere has become unstable.

The north coast reacts particularly quickly to such changes in the weather. The clouds start to move, humidity rises, and showers or unsettled weather conditions often follow. With an easterly flow, however, instead of rain a Calima may set in – that is, a hot, dusty wind from the Sahara – because dry, warm Saharan air then moves in. The clouds begin to drift as soon as the situation changes.

So, whilst the clear view of La Palma is lovely to look at, it is first and foremost an atmospheric signal. It usually heralds that the coming hours or days will be grey, damp or changeable.