Hong Kong’s weather forecaster issued a black rainstorm signal for a second time in six hours on Tuesday as heavy showers drenched the city, paralysing many public services and prompting authorities to suspend classes.

The Hong Kong Observatory raised the highest-level rainstorm warning at 5.50am and said it would keep it in force until at least 3pm. The previous warning was issued at 11.45pm on Monday.

It also said that the North District, Tai Po and Tsuen Wan were being severely affected, warning residents to stay away from watercourses.

A landslip warning was also issued, with the forecaster calling on members of the public to stay away from steep slopes and hilly areas. Violent gusts exceeding 90km/h (56mph) were recorded in Cheung Chau at around 8.35am.