Physical Geography and Climate of Northern Spain's Massifs

Physical Geography of the Galaico-Leonese and Cantabrian Mountains

A) Relief and Geological Structure

The Galaico-Leonese Massif and the Cantabrian Mountains border the plateau to the north. The Galaico-Leonese Massif was fractured and uneven during the Tertiary period. Its distinctive profile is rounded and of low altitude, resulting from continuous erosion. The mountains are separated by deep faults. The most important sierras (mountain ranges) include Segundera, Cabrera, and Hangares. Higher elevations exceed 2,000 meters (m), such as Teleno (2,118 m).

The Cantabrian Mountains are the great massif of Northern Spain, stretching from west to east. Two distinct sectors can be differentiated:

• Western Sector: Predominantly abundant coal strata, which explains the importance of mining activities in this sector. This area reaches the highest altitudes, including Peñaprieta (2,516 m) and Torrecerredo (2,648 m), both located in the Picos de Europa.
• Eastern Sector: Characterized by an abundance of caves due to karstic erosion—the relief resulting from the dissolution of limestone by water action. Altitudes here are generally lower, although some peaks approach 2,000 m.

B) Oceanic Climate Characteristics

The oceanic climate dominates the Cantabrian coast and the Atlantic coast of Galicia. Its essential climatic features are determined by the arrival of Atlantic storms. This dominant climate is defined by its low annual temperature range and the moderating influence of the sea water temperature. This results in mild winters and cool summers. This region also receives the highest rainfall in Spain, distributed very regularly throughout the year.

C) Hydrology and River Systems

The rivers of the Cantabrian and Galician slopes, such as the Bidasoa, the Nalón, the Miño, and the Sil, are short because they originate in mountains close to the sea. They descend strong slopes from their source to the mouth, giving them great erosive capacity. These rivers have a regular flow regime as a result of the heavy rains that fall in this part of Spain, meaning dry periods during summer are hardly noticeable.

D) Deciduous Forests and Vegetation

The characteristic vegetation corresponds to deciduous forests (primarily oak, or roble, and beech), and their distribution coincides with the peninsular areas where rainfall is most frequent and abundant. There is a distinction between pure oak and beech forests, and mixed formations.

These forests are located fundamentally within the Euro-Siberian region, stretching from Galicia to the Pyrenees via the Cantabrian Mountains. Some remnants of these forests may also occur in Mediterranean climates, especially in high mountain areas (e.g., the Catalan Coastal Range, Iberian System, Central System, etc.).