Please note that driving overland from Lhasa to Kathmandu is not a problem in winter. Even if there is a road blockage at high passes, there are road clearing equipments available to clear the blockage. As this is the main trading road between China and other South Asian country, they cannot keep the road close for a long time.

However, going to the Everest base camp can be a problem. Heavy snowfall makes it impossible to drive across high passes to Everest base camp in November and December in Tibet and road to the Everest base camp are usually blocked by snow over high pass. During this time the temperature drops to 20 degree Celsius.