Hong Kong experienced a black rainstorm on Friday, the most serious level of rainstorm warning, which led to severe flooding and disruption in the city. The Hong Kong Observatory measured more than 150 millimeters of rainfall in an hour, the highest since records started in 1884.
The black rainstorm warning indicates that heavy rain has occurred or is likely to occur over Hong Kong, exceeding 70 millimeters in an hour, and is expected to persist. The warning advises people to stay indoors and avoid unnecessary travel, as the rain may trigger flash floods and landslides.
The heavy rain impacted public transport and public services, as many roads, subway stations, and parking lots were flooded with water. Some drivers were stuck in their vehicles and had to be saved by drainage workers. Several subway lines were stopped or delayed because of flooding. Bus, tram, and ferry services were also affected. The government announced the suspension of schools and non-essential work and urged employers to allow flexible work arrangements for their staff.
The flooding also impacted some residential areas, especially in the northern part of the city near the border with mainland China. The government said that water was released from a reservoir in Shenzhen at midnight, which may pose a risk of flooding in some parts of the New Territories. The government arranged vehicles to pick up villagers from six villages that may be affected by flooding and take them to temporary shelters.
The black rainstorm happened just a week after Hong Kong was hit by Typhoon Saola, the strongest typhoon in five years, which injured 86 people and caused hundreds of flight cancellations.
The Hong Kong Observatory said that the weather would improve gradually on Saturday, but there would still be occasional showers and thunderstorms. It also warned of possible flooding in low-lying areas due to high tide.