HONG KONG – Hong Kong issued its first red rainstorm warning of the year on May 4 as downpours caused flooding in areas of the territory, shutting roads and disrupting public transportation.

The Hong Kong Observatory raised the red signal at about 9am local time, which signified downpours of more than 50mm had fallen and more rain was expected across the city. Red is the second-highest storm risk level.

Almost seven hours later, the signal was lowered to amber, which signified that heavy rain has fallen or is expected to fall generally over Hong Kong exceeding 30mm in an hour.

Hundreds of vehicles were submerged in a flooded public carpark in the New Territories area of Lohas Park, while roads were closed and bus services were suspended in parts of the nearby Tseung Kwan O area, according to the South China Morning Post.

About 140mm had fallen in the Saikung district, the easternmost part of the New Territories, between 7.40am and about 9am on May 4, the newspaper reported.

“Under the influence of an upper air disturbance, thundery showers continue to develop over the territory,” the observatory said in a statement. “It is expected that severe rainstorms will continue to affect some areas in the eastern part of the territory”.

All school classes were suspended and hospital services were limited at some clinics in the Saikung district, officials said.

Earlier this week, at least 48 people died after a deluge caused a highway to collapse in Meizhou, a city in China’s Guangdong province. Thirty people were injured and 23 vehicles were found in a pit after the road caved in, China Central Television reported. BLOOMBERG