Big Almaty Lake

Big Almaty Lake lies at 2,511 metres above sea level, held back by an ancient moraine dam. It is roughly 1.6km long and 1km wide, up to 40 metres deep, and the peaks immediately around it rise past 4,000 metres — so the surface sits about 1,700 metres above central Almaty. That gain is enough to drop the temperature by 10–12°C against the city on the same afternoon, and enough that visitors who come straight up from the plain sometimes notice mild breathlessness on the walk from the car park.

The colour comes from rock flour: glacial meltwater carries suspended silt so fine that it stays in the water column and scatters light back at the blue-green end of the spectrum. How much silt is in the water decides the shade, which is why the lake is not the same colour twice:

• May–June: peak melt, maximum silt load, the milkiest and most vivid turquoise
• July–August: fuller and deeper blue-green, warmest and busiest
• September–October: silt settles out, the water darkens to deep blue and reflects the peaks cleanly
• Winter: frozen and snow-covered, no colour at all — come for the white amphitheatre instead

Overcast days flatten the colour badly. If the lake is the point of your trip, go on a clear morning before the afternoon cloud builds over the ridge, then put Shymbulak and Medeu in the afternoon — our guide to day trips from Almaty sets out how the routes combine.