One of great french mountain guide René Desmaisons lead 8 expeditions in Peru (first conquest of Huandoy south face, or first Chopicalqui east ridge) described very well specific mountain conditions in Peruvian mountain range :

Located betwen the large amazonian forest and Pacific Ocean, at about 1 000 kilometers from equator line, high summits are exposed to big temperature and hygrometric changes. Humid air from east to west wind generates a very specific ice conditions. Snow fasten to very steep slopes Ice and snow quality are very different from european mountains. This mountain range offers a great snow variety available for andinism practices.

However, depending on slope 'orientation, snow quality could varying very quickly. On south faces, oppose to sunshine, snow is generaly made of poor quality for cramponning but this quality is not constant, depending on altitude, température or hygrometric. In north face, under sun effects, température changes are very quick. In spite of altitude, snow could became fluid and can flow in big crystal.

Steep slodes are frequently striate bu large fluting : ice-flutes, delivering a lot of routes depending on quality snow (Writer note : for example Ferrari route on Alpamayo). Flutes bottoms are composed by ice, on sildes, made of snow and ice crumbly, you can build solid relays.

Réné Desmaisons
Les Andes vertigineuses
L'Odyssée - Flammarion - 1983

Notes :
Since 1980 years, global climatic situation is deterioring : on all latitudes on earth, year by year, signs of global warming are presents : glaciers are disapearing, seasons are broken (storms during winter, températures too high), big serac falls, flood. Consequences of global warning are dangerous for trekking and mountaineering : avalanches, bad snow, open crevasses.

Caution is necessary, so some advices :
— begin your course early on the morning to reach summit at about 7 - 8 h, descending before high temperature (ice and snow in good conditions),
— refer and employ local guide : they perfectly know their mountains, local climatic conditions and also practice the right way to avoid crevasses and serac falls.

A country stricken by tragedies

Péru is cruelly and regulary stricken by geological or geographical events which murdered thousands of peruvian poeple :
— earthquakes devastate Lima in 1586, 1678, 1742 and 1743 when this town was destroyed and more recently in the south of Lima in 2007 and 2009, parts of glacier falling, like in 1962 where Shacsha village and a part of Ranrahirca village caused more than 4000 deaths, in may of 1970 when Yungay village was broken from maps and buried under mud.
— avalanches made by earthquakes have broken morainic lakes (1941 : Cojup : 6 000 victims)