The death toll from heavy rainfall-triggered mountain torrents has risen to 13, with another 30 missing, in Yuzhong County, northwest China's Gansu Province, as of 12 p.m. Saturday, local authorities said.

Torrential rain began pounding Yuzhong, which is under the jurisdiction of the provincial capital city of Lanzhou, and other areas of Lanzhou on Thursday evening, with the maximum precipitation reaching 220.2 mm by noon Friday. Several townships in Yuzhong have been seriously affected.

A total of 9,828 people in Yuzhong have been relocated to safe areas, and 443 people among those who were trapped have been rescued, according to a news briefing held by the provincial government on Friday night.

Eight local townships have been affected by the mountain torrents, with severe damage to roads, power supply, communication and other facilities. The mountain torrents have also flooded farmlands and damaged houses, according to the news briefing.

At 8 p.m. on Friday, a red alert, the highest alert level in China's four-tier system, for geological disasters was jointly issued by the provincial department of natural resources and the provincial meteorological bureau, warning of potential geological disasters in Yuzhong and the Wudu District, Wenxian County and Kangxian County in Longnan City within 24 hours.

Lanzhou also elevated its emergency response to flooding from Level III to Level I, the highest in China's four-tier emergency response system, at 6 p.m. Friday, said the provincial department of water resources.

At about 2 p.m. Friday, reporters saw floodwater mixed with uprooted trees blocking the roads near Xinglong Primary School in Chengguan Township in Yuzhong, with mud deposits more than 30 cm deep in some sections. Along the roadside, many vehicles lay damaged, while furniture from the ground floors of some houses had been swept to their doorsteps.

More than 2,700 rescue personnel have been dispatched by provincial authorities, along with 980 vehicles and pieces of machinery, and 8,530 sets of emergency supplies.

Search and rescue efforts for the missing, infrastructure repairs, and the evacuation and resettlement of affected residents are underway.

(With input from Xinhua)