Hong Kong is a city well prepared for typhoons, with a detailed warning system that alerts residents to the severity of any approaching storm so that they know how — and how quickly — to respond,But when Typhoon Mangkhut battered the city with 100 miles-per-hour wind gusts on Sunday, its intensity took many Hong Kongers by surprise.

The local news media said the Hong Kong Observatory had labeled Mangkhut the most intense storm to hit the city, a major financial hub, since records began in 1946.

The storm brought drenching rains and 11-foot surges of seawater; shook and damaged buildings; and left dozens injured in the city, after first ravaging the Philippines, where on Monday workers were still searching for survivors in a mudslide in the northern town of Itogon. Dozens were killed in the Philippines and four more in China when the typhoon continued its path northward. In Hong Kong, no deaths were reported.

The Hong Kong government said early Monday that nearly 400 people had sought medical treatment, and more than 1,500 sought refuge in 46 temporary shelters.Cleanup efforts began in earnest on Monday as officials and residents assessed the destruction: broken windows, fallen trees, damaged streets and flooded areas Hong Kong Airport, a central transit point across Asia, reopened after being virtually shut down on Sunday, though there were still many delayed and canceled flights. Rose Marie Nuevo, 32, a domestic worker from the Philippines, said her 11:30 a.m. flight Monday to Manila was canceled and rescheduled for Tuesday. She planned to spend the day waiting in the airport rather than returning to her residence in Hong Kong.