About 71,000 people have been evacuated from their homes in Shaanxi amid the worst flood in 50 years to hit the usually arid province, the local government said Tuesday.

Torrential rains beginning in early September swelled the Weihe River and its tributaries, posing threats to the downstream areas, said Wang Tongchun, chief of the flood control office in Weinan city.

The Lintong hydrological station reported the biggest flood since 1981 on Monday, when water flow topped 5,410 cubic meters per second, said Wang.

The flood crest was expected to arrive at Huaxian county Tuesday night, when the water level would reach 342.2 meters, he said.

Huaxian received 70 mm of rainfall from September 16 to 18, an unusually high volume for this time of year.

Nearly 20,000 people are involved in flood relief efforts - patrolling river embankments and helping evacuate residents from dangerous areas.

The latest round of rainfall battered 89 counties in 10 cities in Shaanxi, topping 31,125 homes and destroying at least 71,500 others, the provincial civil affairs bureau said.

Across Shaanxi province, 35 people were confirmed dead in flood-triggered disasters, including 17 factory workers killed in a massive landslide in the suburbs of the provincial capital Xi'an. Another 15 people remain missing.