Lake Ubales Nature · Caso, Nalón, Asturias Lake Ubales is a small mountain lake of glacial origin located in the council of Caso (Asturias), at around 1,690 metres altitude, on the north slope of Cascayón peak, within Redes Natural Park. It covers an area of 10,546 square metres and has a perimeter of 409 metres; at times of greatest water inflow its maximum depth reaches four metres. It formed in an ancient glacial cirque, a semicircular basin with steep walls where the snow that fed the valley's ice tongue accumulated. It is only accessible on foot, from the villages of Caleao, La Felguerina, La Infiesta or Bezanes along the Los Arrudos gorge, or more conveniently from the San Isidro pass, already in the province of León. Photo: Moisés M (Public domain) What to see and do in Caso