Cinque Terre

The Ligurian coastal climate results in relatively high precipitation, often in intense showers; in such a steep, fractured system, this means rapid peak runoff in brooks as well as temporary springs that “rupture” after rain.

That combination of heavy rainfall, steep terrain, and water-bearing turbidite rock explains why you find such a dense network of small rivers, springs, and wetlands in Cinque Terre, especially along the routes in the valleys.

Cinque Terre is “very wet” for a coastal area: ~1,400 mm of precipitation per year, clearly more than Uccle (820 mm).

Belgium has less total precipitation than Cinque Terre, but the distribution is more even throughout the year; in Cinque Terre, autumn (and partly winter) is clearly the peak season with very intense showers.

When moist air from the sea collides with that steep coastal and mountain wall, it is forced to rise, cools down, and condenses: classic convectional rain (orographic precipitation).

As a result, eastern Liguria (La Spezia, Cinque Terre, Chiavari) is one of the wettest zones in Italy, with locally 1,300–2,000 mm per year.

In autumn and winter, a “Genoa Low” often forms: a low-pressure area in or off the Gulf of Genoa that pushes very humid air against the Ligurian coast.

In such situations, quasi-stationary bands of thunderstorms and rain (“self-renewing thunderstorms”) form that linger in the same place for hours and produce extreme amounts of rain.

In Cinque Terre itself, during the disaster of October 25, 2011, approximately one-third of an annual amount fell in just a few hours, resulting in severe mudslides.

Pascal Brackman