“Within minutes, a river of black water and big stones followed us into the temple,” he said by phone after returning to his home village, Tailagram, in the Rudraprayag district of Uttarakhand.

The temple survived the assault, but when the water receded after a cold night of prayer, Mr. Kukreti found himself standing among piles of dead pilgrims. “Everywhere I looked I saw dead men, women and children,” he said.

Most of the buildings around the temple were destroyed, and the town of Kedarnath, which has grown around the temple, was submerged. After braving cold, hunger and grief for three days inside the temple, Mr. Kukreti and about 400 pilgrims hiked a few miles to an emergency landing pad, and rescue helicopters flew them to a relief camp.

Google has developed a Person Finder application for the Uttarakhand area, and the state government has created a message board on its Web site, where relatives of missing pilgrims are posting their phone numbers and names, and the last locations and pictures of their missing relatives. In a message on the Uttarakhand government bulletin board, Rajneesh, an anxious relative, who uses only one name, said he was looking for his missing brother and sister-in-law and their two children named Honey and Money.

The Himalayan pilgrimage centers have been straining to cope with the disaster. In the past two decades, religious expression has increased in India along with economic growth, and the number of pilgrims visiting religious sites has greatly increased. According to official statistics, 30 million tourists visited Uttarakhand in 2010, up from 10 million in 2001, according to official statistics.

“It is an ecologically fragile region and the Himalayas are young mountains, but there is haphazard construction to serve increasing numbers of tourists and pilgrims,” said Ashish Kothari, an Indian environmentalist and a co-author of “Churning the Earth: The Making of Global India.” “All sorts of hydroelectric projects are coming up in these areas, and anything goes in the name of environment assessment.”