Huayco (also Huaico) is a Peruvian term for the flash floods that occur regularly during the rainy season in the Andes. Often they are regular but minor, such as the one that affected me yesterday in the Chillón valley, blocking the road with mud, boulders and a torrent of water for several hours. Other times they can be more violent, washing away bridges and even towns.
Yesterday for instance, while I was stuck for hours 52 kilometres from Lima thanks to my relatively minor huayco, the district of Chanchamayo in Junin suffered a huge huayco that washed away the road. 12 hours later help was yet to arrive for stricken travellers. That’s usually the way it is; locals having cleared some of the path so cars can pass one by one (in exchange for a small tip from each) long before anyone from the Government shows up to help.