Lahaul and Spiti is surrounded by high mountain ranges. The Rohtang Pass, at 13,054 feet (3,979 m), separates Lahul and Spiti from the Kullu Valley. Lahul and Spiti are cut off from each other by the higher Kunzum Pass, at 15,059 feet (4,590 m).A road connects the two divisions, but is cut off frequently in winter and spring due to heavy snow. The valley is likewise cut off from the north up to eight months of the year by heavy snowfalls and thick icing conditions. A southern route to India proper is periodically closed for brief periods in the winter storms of November through June, but road access is usually restored a few days after storms end via Shimla and the Sutlej in the Kinnaur district.Taken from Wikipedia