Nepal’s Home Affairs Ministry said 20,600 personnel had been deployed and more than 3,100 people rescued.
Survivor Shibu Giri, 44, said a helicopter crew tried three times to rescue him after he became trapped waist-deep in mud.
“I asked them to throw water and food,” Giri told AFP.
The floods were triggered by a glacial collapse, according to the US Geological Survey. Scientists have warned that rising temperatures are accelerating glacier melt and increasing the risk of such disasters.
With mortuaries overflowing, Nepal has begun burying unidentified victims after collecting DNA samples for possible identification later.
The country has appealed for international aid, including “more than a thousand” freezer units to store bodies.
China said 546 people remain missing in Tibet. More than 2,000 personnel are involved in rescue efforts there.