According to historical debris flows records, the more hazardous zones in Portugal are Madeira, Azores and northern continental regions. In fact, the mountainous steep slopes of these regions are frequently overwhelmed by mass movements which directly affect the unconsolidated cover material. Additionally, these regions are prone to extreme meteorological events, namely high intensity rainfall resulting in favorable conditions to debris flow initialization.
In last 35 years, the most relevant debris flows events in Portugal were:
- Madeira Island, on 20th February 2010
- Northern region of Portugal, on 26th January 2001
- Arosa (Cavez, Cabeceiras de Basto), on 27th December 1981