SHANGHAI, July 3 (Xinhua) -- When two typhoons made landfall in Shanghai within three days, the rare sequence became more than just a meteorological record. It was a stress test for one of China's most complex urban systems.
Typhoon Bebinca struck the city at severe typhoon intensity in September 2024. Three days later, Typhoon Pulasan followed, marking the first time since meteorological records began that Shanghai had seen two typhoons within such a short interval.
The storms highlighted a challenge facing the coastal megacity: the overlapping risks of wind, rain, storm tides and flooding brought by extreme weather.
Shanghai's exposure starts with geography. The city sits near the mouth of the Yangtze River and faces the sea, leaving it vulnerable to those overlapping risks. That vulnerability is magnified by scale -- more than 63,000 buildings of eight floors or above, 906 kilometers of rail traffic lines, 13,000 glass-curtain-wall buildings, and 267,000 outdoor advertisements and shop signs.
These figures reflect the density of a megacity. At the same time, they reveal just how many places risk can multiply during extreme weather.
"In the context of global warming, extreme wind and rain events in Shanghai are no longer accidental," said Shi Jiawen of the city's climate center. Such events, Shi said, are becoming more frequent, more intense and more sudden.
From 2021 to 2025, the maximum hourly rainfall in Shanghai's urban area rose 13.3 percent from the previous five-year period, according to Xu Shuangquan, an official with the Shanghai Water Authority. On July 31, 2025, parts of Changning, Putuo and Baoshan districts saw hourly rainfall top 100 mm, surpassing the once-in-a-century threshold.
Typhoon patterns are changing as well. Xu said global warming has contributed to a northward shift in typhoon tracks, increasing the likelihood of direct landfall in Shanghai. Bebinca and Pulasan in 2024, followed by Co-May in 2025, all struck the city head-on, a sequence he described as "historically rare."
For Shanghai, one aspect of resilience now comes down to time: how early a storm can be forecast, how quickly warnings can be delivered, and how much preparation can be completed before severe weather hits.
In March 2025, Shanghai launched an artificial intelligence meteorological application innovation center and unveiled two self-developed AI forecasting models, Yushi ("Rain Master") and Fuyao ("Whirlwind"), which were put into operation during that year's flood season.
Yushi focuses on sudden severe convective weather affecting Shanghai, using three-dimensional radar data to capture the structure and development of thunderstorm cells. Fuyao targets short-term heavy rainfall and thunderstorm winds, rapidly integrating radar, satellite, automatic weather stations and numerical forecast data.
The models can complete inference in 5 to 10 seconds and support updates every 10 minutes. In 13 local severe-convection episodes in 2025, Yushi extended warning lead times by 15 to 45 minutes. Early advisories for severe convection, meanwhile, were issued an average of four hours and 20 minutes ahead of impact.
These margins are critical in emergencies, guiding pump-truck deployment, traffic controls, and targeted warnings down to the district level.
Shanghai has also formalized layered warning mechanisms. For typhoons, meteorological authorities begin monitoring, analysis and AI-based path simulations five days in advance, followed by work notices, joint consultations, warning signals and industry-specific risk alerts as landfall nears. For severe convection, where conditions change faster, the timetable is compressed, with an imminent-warning mechanism activated one hour in advance.
The other test is whether the city can move water quickly enough.
Shanghai has been upgrading chronic waterlogging sites in its central urban area since 1998. By the end of 2025, 370 sites had seen improvements. In 2026, the city planned to complete another 52. In older residential compounds, work has also targeted mixed rainwater and sewage connections, aging drainage networks and weak local discharge capacity.
Since 2024, the city has been developing a system that combines stormwater infrastructure, mobile pump trucks and emergency retention facilities. During storms, the pump trucks can collect rainwater from surrounding areas and move it into storage, allowing the water to be discharged later in staggered releases, reducing the risk of waterlogging when the drainage network is under strain.
At Heping Park in Hongkou District, a leisure space doubles as stormwater infrastructure. Sunken green areas, vegetation filtration, lowered walkways and a lake designed to regulate water levels and store stormwater help absorb heavy rain and safeguard drainage for the park and its surrounding 36-hectare area.
Digital monitoring is enhancing Shanghai's flood response. Since 2025, the city has used AI-powered video inspections to detect waterlogging risks in underpasses and other flood-prone areas. The program now covers more vulnerable locations, enabling earlier detection and faster responses.
The city is also trying to create more buffers before storms arrive. Ahead of Typhoon Co-May last year, coordinated pump-and-sluice operations lowered river network water levels to free up 150 million cubic meters of storage capacity.
The stress on the system was clear. During the same typhoon, Shanghai faced the combined impact of typhoon, rainstorm and high tide, pushing Suzhou Creek -- one of the city's oldest rivers -- above warning levels and driving one monitoring station to a record high.
Shanghai's climate response is increasingly systematic: earlier forecasts, stronger drainage, more storage, faster equipment deployment and data-driven monitoring. The approach is measured in minutes of warning time, cubic meters of storage capacity, pre-positioned pump trucks and video feeds focused on flood-prone streets.
For China's megacities, resilience is becoming a form of daily urban management. As heavier downpours and northward-shifting typhoon risks continue to test city systems, it has to be maintained through constant adjustment in forecasts, infrastructure, emergency plans and the way they are operated. ■
