(Source:Hong Kong Observatory)

Rains and tropical cyclones can lead to floods in Hong Kong.

Hong Kong receives the most rainfall during summer. Our Amber, Red and Black Rainstorm Warning Signals alert the public of heavy rain exceeding 30, 50 and 70 mm respectively within the hour, and that the rain is likely to continue [1]. When the rate of rainfall exceeds the speed of water draining away, water accumulates and results in floods [2].

Meanwhile, frequent tropical cyclones may lead to storm surge [3], which may bring floods to low-lying areas. Depending on where the tropical cyclones land, they affect various coastal regions of Hong Kong. For example, Usagi in 2013 caused a landfall near the east-northeast of Hong Kong, resulting in floods in northern and western New Territories (Lau Fau Shan, Tuen Mun and Tai Po) and Sham Shui Po [4]. Cyclone Manghkut moved near south-southwest of Hong Kong [5] in 2018 and thus brought floods to Heng Fa Chuen, Tai O, Lei Yue Mun, Tseung Kwan O and part of the New Territories [6].

Floods can cause injuries, deaths and destroy property. To protect your family and yourself, you can refer to some tips to prepare for and respond to floods [7] [8] [9].

Prepare Now

  • If flash flooding is a risk in your location, monitor potential signs such as heavy rain.
  • Gather supplies (e.g. batteries and charging devices) in case you have to leave immediately or if there are unforeseeable circumstances such as power cut. Keep in mind each person's specific needs and the needs of pets.
  • Protect your property by moving valued items to higher levels.
  • Learn and practice evacuation routes, shelter plans, and flash flood responses.
  • Farmers and fishpond owners should take necessary precautions to minimize losses.
  • For an update on the status of weather warnings, you may call the Observatory's Dial-a-Weather service at 1878 200 or browse the Observatory's website or mobile apps.

Survive During

  • Depending on where you are, and the impact and warning time of flooding, go immediately to the nearest safe location that you can identify.
  • Do not walk, swim, or drive through floodwaters. Just six inches of fast-moving water can knock you down, and one foot of moving water can sweep your vehicle away.
  • If trapped in a building, go to its highest level. Do not climb into a closed attic. You may become trapped by rising floodwater. Go on the roof only if necessary and signal for help.
  • Listen to radio or television broadcasts for current emergency information and instructions.
  • Stay off bridges over fast-moving water. Fast-moving water can wash bridges away without warning.
  • If your vehicle is trapped in rapidly moving water, stay inside. If water is rising inside the vehicle, seek refuge on the roof.

Be Safe After

  • Listen to authorities for information and instructions. Return home only when authorities say it is safe.
  • Avoid driving, except in emergencies.
  • Avoid wading in floodwater, which may contain dangerous debris and be contaminated.
  • Be aware of the risk of electrocution. Do not touch electrical equipment if it is wet or if you are standing in water. If it is safe to do so, turn off the electricity to prevent electric shock.