Tsomgo Lake, also called Changu, sits at about 3,750 metres in the mountains east of Gangtok, a small oval of cold water cupped in a bowl of bare slopes. It is a glacial lake, fed by melting snow, and it freezes over in winter, when the surrounding hills are white. The Sikkimese hold it sacred, and local lamas once used the colour of its water to foretell the year ahead. In spring the banks are bright with primulas and rhododendrons, and in autumn the air is sharp and clear.
The road to the lake is part of the old trade route that once carried wool, tea and salt between Sikkim and Tibet, and it continues up to the Nathu La pass on the Chinese border at more than four thousand metres. Because this is a border area, visitors need a permit, which has to be arranged in Gangtok through a registered agent or the tourist office, and the army controls access to the higher parts of the road. Rules change from time to time, so check them before you set off.
The ride up from Gangtok is steep and spectacular, with a long run of hairpin bends through forests of rhododendron and fir, then out into open, high pasture. The surface is often rough, with landslides, potholes and patches of ice, and fog can arrive without notice, cutting visibility to a few metres. Winter snow can close the road for days at a time, and the best months are from April to June and from September to November. At this altitude, many people feel the effects of thin air, with headaches and shortness of breath, so go slowly and drink water.
Gangtok, about sixteen kilometres away as the crow flies but much further by road, is the nearest town with proper fuel and supplies, so fill up there and carry an extra layer, since it can be freezing even on a sunny day. The sunlight at this height is strong, so bring sunglasses and sun cream.