More than a year's worth of rain fell in a matter of hours Friday in and around the port city in the south of Buenos Aires province, with entire neighborhoods inundated by the fast-rising waters.

Argentines have been particularly shaken by the fate of two little girls who were travelling with their parents by car when the vehicle became marooned in the floods.

A delivery van driver managed to rescue the two children and their mother and bring them aboard his vehicle but it too filled with water, relatives of the family told local media.

The four climbed onto the roof of the van to try escape but a flood surge then ripped away the driver and the two girls.

The mother survived, as did the children's father but the body of the delivery driver was found on Sunday.

The government has ordered three days of national mourning over the worst disaster in Bahia Blanca in decades.

A hundred people were still unaccounted for but the authorities said that they believed most had survived but were out of reach because of damage to the city's cellphone masts or power cuts caused by the floods.

The receding waters revealed catastrophic scenes in several neighborhoods on Monday of mud-caked streets filled with debris, damaged furniture and cars that had been tossed about by the floods piled up on each other.

AFPTV images showed overturned cars lying in a gully and residents using brushes to try clear their houses of mud.

Nearly 1,000 people who were evacuated from their homes remain in temporary shelters.

- Pope, Messi send condolences -

The storm left much of the surrounding coastal area without power and caused an estimated $400 million in infrastructure damage, according to Bahia Blanca Mayor Federico Susbielles.

Provincial security minister Javier Alonso said 23 schools were badly damaged and that parts of Bahia Blanca were submerged in a meter and a half (five feet) of mud.

The central government has authorized emergency reconstruction aid of 10 billion pesos ($9.2 million).

Soccer clubs and other associations launched campaigns to raise money for the victims.

Argentine football superstar Lionel Messi offered his condolences on Instagram to the victims' families.

"Much strength to all those who are having a rough time in this difficult moment," he wrote.

Argentine Pope Francis, who is still in hospital with pneumonia, said he felt "close to the suffering" of the victims while Italian Prime Minister Giorgia Meloni also sent her condolences.

Some two million hectares of farmland in the country's agricultural heartland were damaged in the flooding.

Environment official Andrea Dufourg said that the extreme weather event was "a clear example of climate change."

"Unfortunately this will continue to take place... we have no other option than to prepare cities, educate citizens, establish effective early warning systems," said Dufourg, who is director of environmental policy for the city of Ituzaingo outside Buenos Aires.

Bahia Blanca has suffered past weather-related disasters, including a storm in December 2023 that claimed 13 lives. It caused houses to collapse and provoked widespread infrastructure damage.