Tides of flood water, rock and mud rushed through the region on Friday bulldozing bridges, homes and entire roads in its pathway.
Thousands of Indian soldiers, police and paramilitary are treating the injured and sifting through the buried homes. Sniffer dogs are being used to locate the bodies.
Many more people are feared buried in the village of Choglamsar on the outskirts of Leh.
Army spokesman JS Brar said the remote Zanskar valley had been cut off by the floods, with roads to the area blocked following landslides and communication links severely affected.
Air force helicopters flew approximately 100 foreign tourists stuck in the Zanskar valley back to Leh, where the airport has remained open, despite flooding in the town.
Nearly 200 other foreigners were stranded elsewhere in Ladakh but efforts were underway to get them back to Leh.
The Indian government said it was arranging for 20,000 bottles of drinking water to be airlifted to the town.
Ladakh is a highly militarised area because of border disputes with both Pakistan and China.
The floods came as neighbouring Pakistan suffered the worst flooding in its history with 15 million people affected and at least 1,600 people killed.