The most intense storm of the summer lashed Shanghai with heavy rain and hail yesterday afternoon, canceling flights and ferries and flooding streets and homes.

A resident wades along a flooded street in Chuansha Town in Shanghai's Pudong New Area yesterday afternoon after a downpour. The heaviest rainstorm so far this summer flooded streets, homes and shops in Chuansha, and caused flight cancellations and the disruption of ferry services in other parts of the city. [Shanghai Daily]

An "orange" alert was declared, the second highest on a three-level scale.

The worst-hit spot was Chuansha in Pudong New Area. It was drenched with 14.1 centimeters of rainfall - 9.6cm in one hour alone - and was pelted by hail.

In the downtown, Changning District recorded the most rain, about 5cm, according to the Shanghai Flood Control Headquarters.

Because of the intensity of the downpour, water collected on nearly 20 streets in Changning and Chuansha at depths between 5 and 40cm, flooding 200 homes.

Part of a dyke along an unidentified river in Chuansha collapsed in the storm, officials said. Water flooded under a nearby elevated road, causing some vehicles to stall. The flood headquarters activated its emergency drainage system and was able to clear the streets by 9pm.

Twenty-four flights bound for the Pudong International Airport had to land at the Hongqiao International Airport or airports in Jiangsu or Zhejiang provinces, 20 flights were canceled and hundreds were delayed. Around 2,000 air travelers were affected by the disruptions.

All ferry services to Chongming, Changxing and Hengsha islands were suspended.

The rain should give way this morning to cloudy skies, which are expected to linger through tomorrow. Today's high should reach 34 degrees Celsius, forecasters said.

The highs will be around 31 to 32 degrees over the weekend, with lows around 26 degrees. Thunderstorms are expected to return on Sunday.