BEIJING (Reuters) – Thunderstorms lashed Beijing on Saturday, disrupting hundreds of flights at one of the world’s largest airports, while authorities warned that rain and wind could cause landslides in the area where a 7.0-magnitude earthquake struck this week.

Beijing city authorities raised their weather alert level early on Saturday afternoon to “orange” from “yellow”, warning that lightning, hail, wind and as much as 70 mm of rain would hit the city, potentially causing flash floods in mountainous areas.

Beijing Capital International Airport Co Ltd <0694.HK urged travelers, in a statement on its website, to check for updates on their flights into and out of the city.

Almost 500 flights were listed as canceled from 9 a.m. until midnight and 182 were delayed at China’s busiest airport, the website showed.

Air China Ltd said on its Weibo social media account that some 137 of its flights in and out of the capital had been canceled as of 11 a.m. (0300 GMT).

Torrential rain storms are fairly frequent in Beijing in the summer months, often causing long delays at the airport.

Other airports affected by the downpours included Shanghai, Nanjing in Jiangsu province, Hangzhou in Zhejiang along the Yangtze River delta.

The others were in northern regions: Shijiazhuang in Hebei, Taiyuan in Shanxi, Lanzhou in Gansu, Xining in Qinghai and Yinchuan in Ningxia.

In a statement, China’s National Meteorological Centre cautioned rescue crews working in Jiuzhaigou, in the southwestern province of Sichuan, to be on alert for landslides and lightning.

Heavy rain was expected across south-eastern China on Saturday, it said.

The extreme weather came after a tornado struck Inner Mongolia on Friday, killing five people, injuring more than 50 and destroying homes in a major city.