LANZHOU - A rain-triggered landslide in Northwest China's Gansu province on Wednesday has cut off a pivotal highway and formed a barrier lake that threatens to burst and flood a neighboring county, local authorities said Thursday.

More than 50,000 cubic meters of rock and dirt cascaded down the side of a mountain in Jingning county Wednesday morning, disrupting traffic on a provincial highway and forming a barrier lake in the Hulu River, the publicity department of the Jingning county committee of the Communist Party of China said in a press release.

Ten people from four families were forced to evacuate from the affected area, but no casualties have been reported so far, it said.

Workers were still cleaning the debris from provincial highway 304 Thursday, but it was hard to tell when traffic would resume as rocks and dirt have continued to slide down onto the road.

Meanwhile, the barrier lake - about 100 meters long, at least 6 meters deep and holding about 120,000 cubic meters of water - remains a threat to thousands downstream of the lake in Qinan county.

The provincial government of Gansu sent a team of geologists and water conservation specialists to the site early Thursday. They were studying the possibility of further geological disasters and ways to discharge water from the dangerous lake.

Torrential rains have hit 22 provincial-level regions in China since last Friday, leaving 111 dead and another 47 missing, the Ministry of Civil Affairs said Tuesday.