On a small area of the Ak-Shiyrak mountain range, glaciers and snow cover are spread over two major river basins of Kyrgyzstan — the Sary-Jaz and Naryn rivers. In an area measuring 30 x 40 km, glaciers cover 435 km², which accounts for 44% of the area. The total number of glaciers is 154. The largest is the Petrov Glacier.
Petrov Glacier is a glacier in Central Tien Shan in Kyrgyzstan, located in the Akshiyrak mountains. It is the source of the main tributary of the Naryn River - the Kumtor River. The area of the glacier is 73.9 km². Its length is 14.3 km, and its width at the lower part is up to 1.8 km.
The southwestern branch of the Petrov Glacier is gentle, closed at the upper part, with few or no crevasses, or they are reliably covered by snow bridges. To the right is an unexplored ice saddle leading to the western branch of the Veeroobrazny Glacier, and a little further is the Petrov South Pass (named after the first explorers, it appears in the classifier under two names - Pervotselinnikov and Mukash Salukunov). After the turn from the ridge, the Shukshin Pass becomes visible - a wide rocky debris couloir (from the east, it presents a relatively easy snow-ice slope). To the south, an unexplored saddle to the eastern branch of the Veeroobrazny Glacier is visible.
After the glacier turns north, crevasses begin to appear under the snow, but they are small and do not pose problems. Gradually, the glacier becomes more open, and crevasses become clearly visible, but all of them are narrow enough that one could fall into them with a backpack. Ahead is the northern branch of the Petrov Glacier with the Sarytor Eastern, Sarytor Central, Rerikh, and Sarytor Western passes.
The morphology of the mountain valley containing the glacier also affects the shading of the glacier and the formation of moraine-glacial and glacial lakes at the glacier's terminus. The higher the enclosing slopes of the valley, the more they cover the glacier's surface, resulting in less solar radiation and reduced melting of the glacier's surface. Water in moraine-glacial and glacial lakes warms up to 8-10 °C on sunny days, activating thermokarst processes that increase the rate of glacier retreat. A vivid example of the active impact of a moraine-glacial lake on the glacier's retreat rate is Petrov Lake at the terminus of the glacier of the same name.
As the lake at the terminus of the Petrov Glacier grew, the rate of its retreat increased. In recent years, it has increased to 57 m per year, which is quite unusual for glaciers of this type (the Petrov Glacier is one of the largest complex valley glaciers in the Tien Shan).
The existing road to the Petrov Glacier and the Petrov Lake passes through a gold-bearing deposit. Naturally, without special permits, access is restricted.
The glacier was named after the topographer, one of the participants in the expedition of Alexander Vasilyevich Kaulbars (1869).
