Hail

This watery meteor, known in Madeira as snow, forms the broad white sheets that in winter sometimes cover the island’s mountains for days on end. Hail falling on the mountains is often accompanied or preceded by thunderstorms, and it always brings a marked drop in temperature along the whole coast.

In the island’s upper region, hail always takes the form of small, irregular, angular lumps. The rounded form, which seems to be due to the lumps beginning to melt as they pass through a thicker layer of the atmosphere, appears only in the middle region, and now and then on the coast. At an altitude of 1,500 metres hail sometimes forms layers more than a metre thick. When it appears between 600 and 800 metres, which is rare, it usually melts within a few hours.

Hail is almost unknown on Porto Santo (‘holy harbour’). Nevertheless, on 4 February 1860 it fell on that island in such abundance that the hills and valleys were covered with it. ‘In the town (vila) there was so much of it’, say the Anais do Porto Santo, ‘that many people filled plates and tubs, and even made sorbet; a thing unheard of among these people’. In our climate hail appears only from the end of autumn to the beginning of spring, and it contributes notably to increasing the volume of water in the springs and streams. It is said that nearly 60 years ago a hailstorm caused great damage to the crops of the parish (freguesia) of Caniçal (‘reed bed’), and it is also recorded that some years ago hail destroyed a good part of the foliage of the fruit trees and other plants in the parish of Canhas. Fortunately, however, such cases are so rare that the Madeiran farmer, when cultivating his land, does not even think of this enemy, so much to be feared in more northerly latitudes.

So as to record in these pages a fuller account of the nature of the meteorological phenomena of snow, frost and hail in the islands of our archipelago, we shall transcribe a few passages from an article on this interesting subject which the co-author of this Elucidário, the distinguished naturalist C. Azevedo de Meneses, published many years ago in the former Diário da Madeira (‘Madeira Daily’).

‘The information on these meteors provided by the various works dealing with the climatology and meteorology of Madeira is so meagre that the few data we now present on them, nearly all the fruit of our own observation, may perhaps be of some interest.

As a rule, snow falls in Madeira only from January to early March, that is, in the period when the cold is most intense, and, we believe, it is never seen below 1200 or 1000 metres. Madeirans who visit or cross the mountains during the winter months call snowflakes folhelho (popular name for snowflakes), reserving the word neve (snow) for hail, which is far more frequent on the island and is also seen at lower altitudes.

During the coldest season, the centigrade thermometer in Funchal sometimes falls to 8 and 7 degrees. If, then, we accept that heat decreases by one degree for every 180 metres of elevation, it follows that on the same occasions the thermometer should read temperatures slightly below zero at altitudes above 1300 metres, which, as is well known, are enough to bring about snowfalls. In our climate snow does not last long, generally melting within a few hours.

Guilherme Teles de Meneses, who made some meteorological observations at the station on the Pico do Arieiro (1700 metres), saw the thermometer there register 2 degrees below zero in November. It is therefore reasonable to suppose that still lower temperatures occur at the same spot in January and February, which in Madeira are the coldest months of the year. In the opinion of the late English naturalist James Yate Johnson, the limit of perpetual snow at the latitude of Madeira must lie at 3,450 metres, an altitude that our Pico Ruivo (‘russet peak’) does not even approach…

During the winter months frosts also sometimes appear on the high points of the island. The crystalline layers of ice that form on certain objects are known to the common people as dente de cão (‘dog’s tooth’, popular name for crystalline hoar frost). We are told that on the north coast frosts usually appear above 600 or 700 metres, but on the south coast we believe they are unknown within the limits of the cultivated region, which only at a few points rises above 800 metres.

Hail is far more frequent on the island than flake snow or folhelho and frosts or dente de cão. It falls most abundantly from November to March, but also appears occasionally in October and April. It is hail that forms those broad white sheets which in the winter season sometimes cover a good part of our mountains for days on end (3 to 15, rarely more).

Hail falls in the mountains every year, but it is not always visible from Funchal. Hailfalls are often accompanied or preceded by thunderstorms, and always bring a drop in temperature in the city. When this meteor appears between 600 and 800 metres, which is rare, it generally melts within a few hours.

Hail in the mountains of Madeira always takes the form of small, irregular, angular pieces, similar in shape to the basaltic sand of the beaches. The rounded form, which is much less frequent, appears only at middle altitudes on the southern and northern slopes, and now and then near the coast. At an altitude of 1500 metres, hail in some years builds up layers more than a metre thick.

Because of the altitudes at which they appear, snow and frost do no damage to the island’s crops; hail, however, can sometimes be harmful, though never as much as in the countries of Europe. It is said that more than 50 years ago a hailstorm caused great damage to the crops of the parish (freguesia) of Caniçal, and Guilherme Teles de Meneses told us that some nine or ten years ago he saw hail destroy a good part of the foliage of the fruit trees in other areas of the parish of Canhas. These cases, however, are fortunately so rare that the Madeiran farmer, when cultivating his land, as stated above, never even thinks of this enemy, so much to be feared in more northerly latitudes. He fears droughts far more, and their effects are indeed much more disastrous for agriculture, especially in places that irrigation water does not reach.’