It is frozen from October to late May and has a maximum flow in June with the snowmelt. It is navigable in small boats for about 570 kilometres (350 mi) to near Markovo. West of Markovo it is in the Anadyr Highlands (moderate mountains and valleys with a few trees) and east of Markovo it moves into the Anadyr Lowlands (very flat treeless tundra with lakes and bogs).