Despite the fact that cold weather has been widely documented as a major factor that can elevate the mortality in a subtropical population due to a lack of adaptability, the disastrous impacts from a major cold event in East Asia caused by a super El Niño event in January 2016 have passed largely unreported. In order to minimize the catastrophic risk from such events given ongoing concerns about climate change, as also noted in the Sendai Framework for Disaster Risk Reduction 2015–2030 (SFDRR), it is important to evaluate the individual- and community-level shifts in mortality patterns during such cold waves, in order to develop health protocols for surveillance and disaster planning.

This study evaluated the impacts of the 2016 cold wave on mortality patterns in Hong Kong because this city has been highlighted as a city with severe negative impacts from the disaster by social media. Based on a sensitivity analysis, we found significantly higher daily mortality for up to ten weeks during this cold wave compared to the same calendar days between 2007 and 2015. We also found that the short-term impact of the cold wave was prolonged and fatal, with the potential to increase the mortality across the city for up to five weeks compared to the pre-disaster period. An examination of the individual- and community-level shifts in mortality patterns reveals that the unmarried and economically inactive were most vulnerable during the 2016 cold wave, and respiratory diseases were the greatest medical problems, while age and gender effects as well as cardiovascular diseases did not enhance the fatal effect. The excessive mortality was citywide, and not limited to particular locations or specific characteristics of a community within the city. Based on the results, disaster education as well as social and health services should be provided to all local people for an extended period in order to minimize the fatal and prolonged effects of future cold waves.