Galerna

A galerna is a sudden and violent storm with strong wind gusts from the west or northwest that affects coastal areas of the Bay of Biscay, predominantly during spring and fall. It especially affects the central and eastern part of the Spanish north coast (Asturias, Cantabria, and the Basque provinces of Biscay and Gipuzkoa) and the southwestern region of France (Touraine, Berry, Deux-Sèvres, Vendée, French Basque Country, Quercy, and Brittany). The name comes from French "galerne" and that originates from Breton (gwalarn), a wind from the northwest.
Description.
It is caused by the passage of a channeled cold coastal front, a type of coastally trapped disturbance. They usually occur during warm and calm days when a cold front causes a sudden change in wind direction and intensity that can exceed 100 km/h. The sky darkens and there is a sudden decrease in temperature of up to 12°C in 20 minutes, rapid drop in atmospheric pressure, and a rise in relative humidity. The resulting wave heights in the coastal ocean range from rough to very high on the Douglas sea scale.
Because of the associated weather and sea condition change, they are some of the meteorological events most feared by mariners and fishermen in the Bay of Biscay, especially historically. Currently, weather forecast models are able to predict the precursor conditions to galernas, reducing their potential risks, but predicting the exact timing of their occurrence remains a challenge.
Galernas throughout history.
Galernas have caused many fatalities throughout history. One of the most damaging events occurred on April 20, 1878 and it was known as the "Galerna of Easter Saturday". It is featured in the novel "" by José María de Pereda. During that day, fishermen tried to reach the coast in their launch boats to no avail, while their families watched from shore. 322 fishermen died along the Cantabrian coast (132 from Cantabria and 190 basque) and it caused a commotion throughout the country. The response to this disaster caused the introduction of several maritime safety improvements (e.g., flush deck, weather reports, search and rescue operations). Even with these improvements, many galernas continued causing fatalities.