The number of deaths from record rains and flooding in Argentina climbed to 59, officials said as they searched Thursday for about 20 people still missing.

Most of the bodies were found Wednesday after a second day of record rainfall deluged Buenos Aires and nearby La Plata, where flooding submerged cars and sent people scrambling to rooftops for safety.

President Cristina Kirchner declared three days of national mourning starting Thursday in honor of the victims.

Kirchner surveyed the devastation by helicopter the day before, flying over La Plata, a bustling university town of about one million inhabitants where she grew up, about 60 kilometers (40 miles) south of the capital.

Several people perished in Buenos Aires and its suburbs, while various others were missing and feared dead.

"There are still about 20 people who have not been found," said Argentine Deputy Security Minister Sergio Berni.

Lorena Bermet, 36, recounted how she sought refuge on the roof of her house with her husband and two young children until rescuers were able to rescue them by boat.

The building now is uninhabitable, she said, on the verge of collapsing and filled with snakes and rats that invaded after the flood.

"I've lost everything," she told AFP at a relief center where she sought assistance.

"I'm here to get clothes and shoes for my children," she said, adding that her family had escaped with little more than the clothes on their backs.

Residents of the most heavily flooded neighborhoods trickled back home after a staggering 40 centimeters (16 inches) of rain fell on La Plata during a two-hour period late Tuesday into Wednesday, knocking out phone and power lines and leaving about half the city in the dark.

Flood waters reached two meters (seven feet) in some places, turning city roadways into raging rivers.

"I heard piercing screams, I saw bodies float by. Nobody came to help, not a firefighter, or a policeman or a soldier," an outraged La Plata resident told local television.

In Buenos Aires, more than 15 centimeters of rain -- an April record -- fell between late Monday and early Tuesday, according to the local weather service.