Hi Ayush,
Roads to Kalpa and Sangla close in February. You can get stuck for days if heavy snowfall occurs. However, as soon as the weather improves, the roads to these tourist destinations in Kinnaur Valley are opened up. It is recommended to not travel there in February though. The best time to visit this place is from September to November. Read others' experiences to get an idea about when you should plan your trip! Attaching a few below.