The 20-hour storm that hit Beijing on Saturday claimed the lives of 37 people — 25 of the deaths were caused by drowning.

Millions of people across the capital were hit by the deluge and thousands were evacuated from their homes. The flooding caused losses of at least 10 billion yuan ($1.6 billion), according to the Beijing municipal government.

The southwestern district of Fangshan was the hardest hit. Of the 56,933 people evacuated in the city, 20,990 came from Fangshan. There were two landslides in the district.

The rainfall reached 460 millimeters in the district, the highest ever recorded, according to the government. In the rest of Beijing, the average was 170 mm, the highest since 1951.

The Juma River, which runs across Fangshan, flooded and its maximum volume reached 2,500 cubic meters per second, a flow rate "rarely recorded", according to the Beijing government.

Few Fangshan residents were prepared for the downpour, which occurred almost without warning.

Guo Yanwei, a 25-year-old who works at the Changkuang coal mine in Fangshan, was holding a party for eight people at her home.

At 5:30 pm, she became aware that the water had reached her doorstep. Just 10 minutes later, the floodwaters had reached a depth of 1.3 meters.

"I noticed the weather forecast on Friday, but we did not know the rain would be so overwhelming and flood my home so quickly," she said. Guo's sister carried her son to the second floor of an adjacent building. Guo and her friends climbed onto the roof of her house.

Soon, all 50 residents of Guo's village had scrambled onto their roofs in search of temporary safety. Two people shared one umbrella in the forlorn hope of avoiding the unstoppable rain. Some residents tried to climb over the wall that surrounds the neighborhood, but the floodwater was so powerful that some parts of the wall looked as if they were about to collapse and could not support them. The residents stayed on the roofs.

Most of the residents work at the coal mine. They called the mine administrators for help and at around 10 pm a rescue team was sent to the neighborhood to provide help for the women and children.

"We left the neighborhood barefooted, because the flood brought so much mud that our shoes got stuck," said Guo Yanwei. Electrical items such as computers, refrigerators and air conditioners were destroyed by the flood. "I only managed to grab an expensive camera that I bought recently.

The neighborhood was still a mess on Sunday morning, according to Guo. Five cars floated in the waters, and most of the residents were given shelter in a meeting hall at the mine.

"Underprivileged people like us are always at great risk when faced with natural disasters," said Guo Yanwei. "So we need more help from the government."

Meanwhile, Li Minying and her family, also in Fangshan district, were lucky. The flood smashed the water pipes, but on Sunday morning the district government began providing drinking water for the 50 households in Xixinfang neighborhood. At least clean drinking water is no longer a concern for the families.