A wall of water crashed through a small city in southwest Colombia overnight, killing at more 154 people across the city and leaving 220 missing when an overflowing river washed away trees, vehicles, houses and everything else in its path.

400 were injured in the deluge, caused by heavy rains a short time earlier. Colombia’s President Juan Manuel Santos said Saturday that more than 154 people had perished.

The president warned earlier in the day that the death toll could rise as the search for survivors continues and declared a state of emergency for Mocoa, the city of about 40,000 near the southern border with Ecuador.

“We don’t know how many more there are going to be, we are still searching,” President Santos said.

The torrential rains triggered what the Colombian Army called an “avalanche” of muddy water from the Mocoa River and its tributaries. Soon the city’s streets filled with rushing water that toppled homes, ripped trees from their roots and carried off cars and trucks.

Witnesses said buildings vibrated as the muddy waters swiftly swept through the city. Many residents didn’t have time to scramble to rooftops or escape to higher ground. Some were killed while sleeping.

Mocoa’s mayor Jose Antonio Castro said houses in 17 neighborhoods were wiped out.

“A big portion of the many houses were just taken by the avalanche, but above all the people were warned with enough time and they were able to get out,” Castro told Sky News.

Herman Granados, a doctor at the local hospital, said he worked through the night to help victims. The hospital was quickly running out of supplies and didn’t have enough blood on hand to treat patients, he added.

“Under the mud, I am sure there are many more (people),” Granados told the Associated Press.

Bridges have also been swept away.