BEIJING - Torrential rains that lashed large swaths of northern and southwestern China from Friday night to Saturday have killed at least 13 people, authorities said.

In Beijing, at least two people were killed and six others injured as strong winds toppled rooftops in two villages in the city's suburban Tongzhou district, the Beijing Emergency Medical Center said.

A third person, also in Tongzhou, was killed after being struck by lightning. The fourth, head of a police station in suburban Fangshan district died of electric shock from a fallen electric wire in waters while rescuing trapped villagers.

The largest rain in 40 years that started thrashing the city around 10 am Saturday has cut off traffic on some roads inundated by waters and also severely disrupted air traffic.

About 475 flights have been canceled and 80 others delayed by more than one hour by 11 pm, according to the Beijing Capital International Airport. The airport's operation was starting to resume as the rain began to subdue.

Beijing received 147 mm of precipitation on average as of 10 pm, with a township in the suburban Fangshan district hit by the largest of 366 mm, according to the Beijing Meteorological Bureau.

The agency issued its first orange rainstorm alert warning since 2005 Saturday evening as the rain is forecast to last over 20 hours till Sunday morning.

Chinese meteorological authorities use a four-tier color-coded weather warning system from "blue", "yellow" to "orange" and "red".

In the northern Shanxi province, four people were killed and one missing at 3 pm after the pickup truck they were on board were carried by flood waters to the middle of a river in the city of Shuozhou while crossing the river, rescuers said.

The rescue operation was still ongoing.

In the southwestern province of Sichuan, six people have been killed in rain-triggered landslides in Weiyuan county, according to the provincial flood control and drought relief headquarters.

Heavy rainstorms battered many parts of Sichuan from Friday night to Saturday morning, with seven counties reporting rainfall of more than 100 mm.

Meanwhile, a railway line linking Baoji of northwest China's Shaanxi province with Chengdu of Sichuan province was cut off Saturday night due to a landslide on a section in Shaanxi, the Xi'an railway bureau said.

Nearly 1,000 workers were braving heavy rains to clear the mud and rocks to resume the services.