Twenty people were killed and four were declared missing when 71 million cubic metres of water streamed out of the Zeyzoun dam, near the town of Hama, about 350 kilometres (220 miles) north of Damascus.
Unconfirmed reports said there might be up to 100 dead.
Several villages were swamped under four metres of water, and crops and power lines were swept away.
Helicopters and rafts undertook a search and rescue mission on Wednesday.
With much of the water now receded, trucks and bulldozers have been trying to carve a way through the mud to search for survivors and help with the clear-up.
President Bashar al-Assad has promised compensation for victims, and the Syrian Government has ordered an investigation into the incident.
It is still unclear what caused the collapse.
Like most of the Middle East, Syria suffers from chronic water shortage, but this year, the winter lasted longer than usual, with heavy rains throughout.
Initial reports now say the dam may have been filled with at least five million cubic metres of water more than it can hold.
Devastation
Many local people managed to flee to safety after noticing cracks in the six-year-old dam on Tuesday afternoon.
They returned to a scene of complete devastation on Wednesday.
Hundreds of homes have been destroyed in the northern al-Ghab area in Syria, and entire crops have been lost because of the floods caused by the collapse.
"We've lost everything: our house, our land, our income. We are finished," Abdel Salam Issa, a villager from Zeyzoun, said.
BBC correspondent Kim Ghattas in Zeyzoun says that Mr Issa's house was completely levelled after a torrent of water and mud flooded his village.
Mr Issa's house is the closest to the dam, and our correspondent says there is nothing left of the village.
She says tonnes of sand and stone from the dam's structure have covered the houses, and only a few walls are still standing with the dome of the village mosque rising from underneath the rubble.
The villagers have set up tents to sleep in overnight and are waiting for help from the government.
Streets were littered with the bodies of dead farm animals and belongings swept out of homes by the force of the water.
'Run'
"It started trickling out in the afternoon, and that's when people started running," a man in the village of al-Ziyarah told the Reuters news agency.
"People drove past us yelling 'run, get out now' so we put everyone in the car and took off", another villager, Naafi Fawaz, told the news agency as he surveyed the damage at his flooded house.
Because most of them were working in the fields it was easy to gather everybody in buses and on tractors.
There are reports that cracks had started appearing a few days earlier, but Mr Issa insists no-one saw anything before Tuesday afternoon.
The dam, on the Orontes river, is one of about 150 in Syria, mainly used for irrigation.
It was built in 1996 for irrigation purposes, and collects rain water and receives water from the Orontes River.