Peru Misti Laguna Aguada Blanca Cliff Mossy Volcanic Rim

#easytravelpost El Misti (5,822 m) is Arequipa's backyard volcano, and the Aguada Blanca reserve at its southeast foot holds a string of shallow lakes at 4,200 m with a cliff rim of pumice where moss and lichens paint the rocks orange and green. I took the public bus to Pampa Cañahuas (S/15, 2 h), hitched with a wool truck to the Aguada Blanca ranger station (S/5 cash), then walked 3 km to the first lake—Laguna Blanca, yes, but the mossy rim is on the unnamed tarn 500 m east, where a 30 m pumice cliff leaks groundwater and grows a 2 m band of moss no photo captures. Reserve fee S/5, ranger cash. Misti summit is a 2-day climb from here (permit via Arequipa mountaineering club, guide mandatory), but the lake rim is a half-day. Mistake: I came in April (wet season tail) and the pumice sucked my boots off—gaiters essential, the rock is volcanic popcorn. Another: I tried to filter lake water without realizing it's alkaline brine—gut revolt in 10 minutes. Carry all water from Arequipa. Aguada Blanca is also vicuña central; I counted 14 before 9 am. The ranger said the moss band moves up and down 5 m a year with the water table, so the cliff "painting" is never the same twice. If a volcano erupts tomorrow, does the moss band become the only archive of what the rim looked like?