Local officials said 85 bodies had been recovered. With 123 people still missing and feared dead, the death toll was expected to rise.
Thousands of trees from the heavily-logged area were swept down the river after two days of rain, knocking down bridges and destroying houses, Dutch tourist Leo Zwetsloot told BBC News Online.
"Houses are crushed under trees and people are stuck in their houses," he said at a hotel in Bukit Lawang village. "A lot of the houses are swept away. Totally gone."
More bodies were found Tuesday morning in the wreckage, and mourners at a local mosque washed bodies and said prayers for the dead.
Five foreigners — two Germans, two Austrians and a Singaporean — were confirmed among those killed. Most of the victims were villagers: local traders, tourist guides, guesthouse workers and their families. Names of the victims were not immediately released.
Days of heavy rain triggered a surge Sunday night in the Bahorok River, which winds through the village of Bukit Lawang. Dozens of inns and restaurants that line its banks were destroyed by the torrent of water, mud and logs.
Holding a white T-shirt belonging to his 3-year-old daughter who drowned in the currents, Muhammad Yusuf, a tourist guide, sobbed: "She used to wear this when she rode her bicycle. I've lost everything."
On Tuesday, the Bahorok River still raged and electricity, phones and other basic services were out. Yet people were trying to get their lives back together.
"What are we going to do now?" said Lebeh Muktar, as he surveyed the remains of his village, which lies 45 miles from the north Sumatran provincial capital of Medan. "Everyone knows someone who was killed. Why us?"
Hopes of finding people alive beneath the debris faded.
"Looking at the conditions at the moment, there is a very small possibility of finding anyone alive," said Lt. Col. Aman Depari as rescuers around him made stretchers out of branches and leaves.
Despite the immense tragedy, there were stories of dramatic escapes.
Americans Tyson Murphy, 27, and Tommy Connelly, 26, both from California, said they climbed trees to get away from the deluge, clinging to the branches for a 1½ hours.
When the waters subsided, "we each kissed our respective trees and took a branch with us," said Connelly, of Ladera Ranch.
"It's one of those things you think will never happen to you," said Murphy, of Laguna Beach, sporting dreadlocks and a Bob Marley T-shirt. "I just said a couple of prayers."
Murphy and Connelly were among nine foreigners who had been trapped on one side of the river for 24 hours. They were pulled 30 yards across the river to safety using a climbing harness and a rope.
"It was the most horrible thing I have ever seen in my life. It was the worst nightmare I have ever had," said Zwetsloot, who was among the nine trapped foreigners.
Officials blamed the flood on illegal logging in the jungles above the once picturesque town of 2,500, which has long drawn backpackers from across the world to its orangutan reserve.
Another possible cause of the destruction, locals say, was that the government had ordered hundreds of trees felled for the construction of a major highway from neighboring Central Aceh district, about 125 miles from Bukit Lawang.
Local officials said that hundreds of thousands logs had been blocking a waterway in the upper reaches of the mountains, and came crashing down into the valley when the water pressure became too great.
Massive logging disrupts the natural absorption and flow of rainwater from the highlands, triggering floods and landslides.
Poor coordination among rescuers meant that casualty figures, including those missing, remain confusing.
Five foreigners were listed among the dead on Tuesday: Two Germans, two Austrians and a Singaporean. Earlier reports said an Australian was also killed, but officials in Canberra disputed that.
Police Sgt. Bomer Pasaribu said at least 80 people died and 123 people were reported missing. That figure did not include several bodies discovered Tuesday, and another local official, who goes by the single name Endang, put the death toll at 85.
A bulldozer shifted huge branches and boulders on the riverbank. Two large tourist buses remained overturned on their sides.
Despite the devastation, officials said the several dozen orangutans in the reserve, located less than a mile up the valley from the river, appeared unaffected by the disaster.
Hundreds of people die each year in floods in Indonesia, an archipelago with 210 million people.
Tourism had been the mainstay of the village since the orangutan reserve was established more than 20 years ago.