Tropical Cyclones


    Tropical cyclones, also known as typhoons or hurricanes, are among the most destructive weather phenomena. They are intense circular storms that originate over warm tropical oceans, and have maximum sustained wind speeds exceeding 119 kilometres per hour and heavy rains.

    However, the greatest damage to life and property is not from the wind, but from secondary events such as storm surges, flooding, landslides and tornadoes.

    Tropical cyclones are referred to by different names depending on where they originate in the world.

    • Hurricanes occur in the Atlantic Ocean and the eastern north Pacific Ocean.
    • Typhoons occur in the western Pacific Ocean.
    • Tropical cyclones occur in the south Pacific Ocean and Indian Ocean.

    From 1998-2017, storms, including tropical cyclones and hurricanes, were second only to earthquakes in terms of fatalities, killing 233 000 people. During this time, storms also affected an estimated 726 million people worldwide, meaning they were injured, made homeless, displaced or evacuated during the emergency phase of the disaster.

    Over the past 30 years the proportion of the world’s population living on cyclone-exposed coastlines has increased 192 percent, thus raising the risk of mortality and morbidity in the event of a tropical cyclone.


    The health impacts of tropical cyclones depend on the number of people living in low-lying coastal areas in the storm’s direct path, the built environment including building design, and whether there is sufficient time for warning and evacuation.

    Tropical cyclones, may directly and indirectly affect health in many ways, for example by: 

    • increasing cases of drowning and other physical trauma; 
    • increasing risks of water- and vector-borne infectious diseases; 
    • increasing mental health effects associated with emergency situations; 
    • disrupting health systems, facilities and services, leaving communities without access to health care when they are needed most;  
    • damaging basic infrastructure, such as food and water supplies and safe shelter.

    When tropical cyclones cause floods and sea surges, the risk of drowning and water- or vector-borne diseases increase. Additionally, flood waters may contain sewage and chemicals, hide sharp objects made of metal or glass and electrical lines, or host dangerous snakes or reptiles, which can cause diseases, injuries, electrocution and bites.

    WHO Response

    WHO works with Member States to build resilient and proactive health systems that can anticipate the needs and challenges during emergencies so that they are more likely to reduce risks and respond effectively when needed.

    During disasters, such as tropical cyclones, WHO helps to restore primary care services so that facilities can deliver essential services, including immunization, basic treatment for common illnesses, acute malnutrition and maternal care while ensuring the ongoing supply of medications for people living with HIV, tuberculosis or diabetes.

    As the health cluster lead for global emergencies, WHO also works with partners to respond to:

    • ensure appropriate food supplementation; 
    • assemble mobile health teams and outreach;
    • conduct epidemic surveillance, early warning and response;
    • call for emergency funding to support health action.


    All →
    Preparedness for cyclones, tropical storms, tornadoes, floods and earthquakes during the COVID-19 pandemic

    The WHO health advisory provides guidance to countries on adapting all existing preparedness and response plans and procedures for natural hazards such...

    Chemical releases associated with cyclones

    Cyclones can be hundreds of kilometres wide and can bring destructive high winds, storm surges, inland flooding, lightning and, occasionally, tornadoes....

    Preventing drowning: an implementation guide

    This guide provides practical steps to reduce drowning – one of the world’s most preventable, neglected and pressing public health issues....

    Mass casualty management systems : strategies and guidelines for building health sector capacity

    The common gaps in health system preparedness around the world are generally well understood, but they are often not addressed in a comprehensive and systematic...