Canaria: Panza de burro

For almost one month I have been trying to see the stars from our terrace on the south of Las Palmas. Pretty much all the evenings, the sky was completely or partially covered by dense white clouds. Although I didn’t have luck in seeing the falling stars on the 12th of August, I am lucky to see in person what the canary inhabitants call “Panza de burro,” in English translated to “the belly of the donkey.”

During the summer months, the Azores archipelago is trapped under a high pressure center, also known as the Azores anticyclone, that moves westward towards Bermuda. This anticyclone creates a constant northern airflow – trade winds – that reach the Canary archipelago. Since the majority of the islands are higher than 1500 m, the fresh and humid trade wind gets blocked by the mountains on the north of every island, except Lanzarote and Fuerteventura (the flattest two). Additionally, the trade wind also hits among a stronger and drier wind that is found exactly above 1500 m, creating a dense sea of white clouds. La panza de burro functions as a sunscreen, literally meaning that it protects the north of each island from the powerful Sun. But does it really?

Credit: Canaragua
From left to right: El Hierro, La Palma, La Gomera, Tenerife, Gran Canaria, Fuerteventura, Lanzarote with Isla de Alegranza & La Graciosa on the north.
Credit: Cancograncanaria

Sometimes when I am running some errands around Las Palmas I feel the air being extremely hot and heavy. This is no greenhouse effect but a phenomenon denoted cloud blanket effect. The infrared radiation coming from the Earth’s surface bounces back down as it is reflected back by the underside of the panza de burro. The albedo (percentage of any surface reflectance in respect to the radiation that reaches the same surface) in this case can reach 90% which is double the average of Earth’s albedo. Although it is difficult to understand this concept, the infrared radiation causes an imbalance on Earth’s climate forming a scorching effect in the atmosphere.

The IR is a longwave radiation that ranges from 700 nm to 1 mm.
Credit: Innovationtoronto

La panza de burro ceases to form between the end of August and September, when the Azores anticyclone has moved towards Bermuda. Finally, this is a better time to visit the Canary Islands, especially if you want to stay on the north of each island, where the freediving spots are crema. I have the fortune to stay here longer, so I might update you on how it goes, vale?

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