Starting from the village of Lloa (3030m) I walked up the long and winding road to the Refugio (4600m) and the crater rim (4794m). A rapid ascent of 1764 meters took me 2 hours 45 minutes. Because I arrived at the crater about 9:30am it was already buried in clouds. By 2:45pm I made the call to spend the night in the Refugio at 4600 meters, hoping for clear skies the next morning. Various internet reports by travellers spoke of how cold it is up here; even with the snow and pea-sized hail they obviously were not written by Canadians.
My overnight gamble paid off: a 5:45am rise provided fantastic views of the surrounding countryside and mountain peaks as well as the Guagua crater. I spent five hours peaked on the crater rim taking in the views and snapping pictures.
The picture above is taken from the dirt road upon approach. Below: the October 1999 ash cloud column.