Hong Kong felt the brunt of Super Typhoon Mangkhut on Sunday as violent winds and intense rain swept through the city, leaving a trail of destruction in their wake.
Nestled within the intertropical convergence zone – an area where northeast and southeast trade winds converge – Hong Kong is no stranger to stormy weather.
The Observatory issues its highest No.10 storm signal when sustained wind speeds top 118 kilometres per hour, with gusts exceeded 220 kilometres per hour. The last T10 cyclone – Typhoon Hato – hit countries across southeast Asia last year, leading to 10 fatalities in Macau and 14 elsewhere. The cyclone caused 129 Hongkongers to seek medical help.
Hong Kong has been rocked by multiple T10 cyclones throughout its history, but there were several factors that made Mangkhut the strongest typhoon to hit the territory since records began.
Wind speed and circulation
According to data collected by the Observatory, Mangkhut had the highest maximum sustained wind speeds when compared to previous T10 storms – topping 220 km per hour. The maximum sustained wind speed can refer to any point in time during the entire life of the typhoon.
The maximum sustained wind speed of Mangkhut was 55 km per hour faster than Hato, and 15 km per hour faster than the previous record-holder – Typhoon Hope.
Mangkhut also had an extensive air circulation and travelled at 48 km per hour, while normal storms average a speed of 32-25 km per hour. This meant that, despite being relatively far away, the super typhoon brought significantly dramatic weather to Hong Kong.
High storm surge
Despite the low sea level at the time, Mangkhut had the highest storm surge of previous T10 storms, according to the Observatory.
At Tai Po Kau, the surge reached 3.38 metres, while at Quarry Bay, it was recorded at 2.35 metres, resulting in flooding in low-lying areas. This was in contrast with a 3.23 metre high surge in Tai Po Kau during Typhoon Hope in 1979.
Leung Wing-mo of the Hong Kong Meteorological Society told HKFP that the city was saved from further flooding by the low sea level at the time: “[T]o a certain extent, we are lucky [as] the closest approach was when we didn’t have a high tide.”
According to reports from residents of flood-prone Tai O on Lantau Island, water levels reached up to 3.9 metres in low-lying Kat Hing Street. Locals continued to be evacuated late into Sunday night, as stilt houses in the coastal fishing village were engulfed by waves.
Storm surges of up to four metres high flooded low-lying areas and gale force winds caused buildings to sway back and forth. In its aftermath, pedestrianised areas were littered with shattered glass and mangled trees, grinding the city to a halt the next day as commuters battled their way through debris. The government was subsequently criticised for not suspending work for the public.
“The damage is extensive, particularly in the Sha Tin area. I’ve never seen anything like that – flooding of the Shing Mun river, to that extent,” Leung told HKFP.
Flooding from Shing Mun River reached 1.5 metres at its highest point, local media reported.
Typhoon Ellen in 1983 wrought an estimated HK$392 million worth of destruction to livestock and crops, while Typhoon Hato caused HK$8 billion worth of damage across the territory.
Leung said that the region can expect to see more extreme weather as global warming worsens: “We have to prepare for the long-term, because scientists expect that we’re going to have more of these events in the future.”
“As far as the short-term preparation is concerned, the government has done an excellent job,” he said. “But as a whole, Hong Kong is not prepared for this kind of natural disaster – you see flooding, broken windows and buildings breaking down… the government and other professionals should focus on the possibility of more severe weather in the future.”
As residents return to daily life, evidence of the typhoon’s destructive power lies scattered on the streets – in tiny shards of glass and mangled branches. However, it appears that Hongkongers should prepare themselves for similar storms in the future.