An extreme event between The Little Ice Age and the 20th century: the snow avalanche cycle of 1888 in the Asturian Massif (Northern Spain)

Abstract

Between the late Little Ice Age (LIA) cold stage and the early 20th century warmer scenario, a transitional regime characterized by an unstable climatic pattern generated a series of climate extremes affecting mid-latitude mountainous areas, as the Asturian Massif. There, the 1888 snow avalanche cycle appears as the most significant event, standing out among the rest of avalanche cycles recorded in this area during the 1800-2015 period both in terms of the number of damaging avalanches and damages caused by them. Among the factors that explain this event stands out the orographic precipitation phenomenon; the interaction of a cold and wet air mass originating from the North Atlantic with the relief of the Massif, which led to extraordinary snow thicknesses (>2 m) at very low altitudes (500 m a.s.l.), especially in the north-facing, Asturian versant of the Cantabrian Mountains. This allowed the triggering of avalanches in slopes gentler and in lower altitudes than usual, covering longer distances; consequently, avalanches reached more easily the settlements, generally placed at the bottom of the valley or in middle slope positions. The greater impact on the settlements, which suffered 84% of the damages, was the cause of this episode’s high socioeconomic impact (29 people dead, 34 injured, 123 heads of cattle dead, 124 buildings destroyed). These events occurred at a time when the mountain villages were highly populated and subjected to intense exploitation, coinciding with the development of new communication infrastructures in the upper parts of the Massif. Therefore, the 1888 episode constitutes a good example of both the impact of hydrometeorological events in mountain environments under high demographic pressure, and of climate extremes involved in a transition period from cold to warmer weather conditions.