Introduction to windstorms

Air is always moving. Wind is one of the most basic parameters of our weather, but also one of the most destructive hazards on our planet. Literally, “a disturbance of the atmosphere”, storms come in many forms and sizes. The most intense windstorms on earth are tornadoes, which may be only a hundred metres across and last for last for less than an hour, but which can destroy anything in their path. Tropical cyclones (also known as hurricanes or typhoons) are revolving storms that can reach sizes of many hundreds of kilometres and devastate large areas with wind speeds of more than 120 km.hr-1. Extra-tropical cyclones are also revolving storms, which can extend to thousands of kilometres and with a lifetime of days to weeks, potentially causing extensive damage at continental scale.

Windstorms are associated not only with wind, but also with rain or snow, and often with hail and lightning. This is particularly the case for tropical cyclones, which are typically most feared for their winds at sea, for the associated ocean storm surges along the coast, and for their rainfall once they move inland. In the devastating 2017 hurricane season in the Atlantic, Hurricanes Harvey, Irma, and Maria caused serious damage in the southern United States and nearly destroyed multiple Caribbean islands through powerful winds, heavy rainfall and storm surges. Initial estimates gave more than 200 people reported killed, more than one million affected, and damages of nearly 100 billion USD[1].

The damage caused by a windstorm depends both on the vulnerability of the affected society and the severity of the storm. Winds, floods and storm surges can damage homes and infrastructure, such as roads, power supply, and communications, but factors like strong building regulations, a history of previous exposure to storms, and good storm warning systems can all reduce the impact of a storm. Advances in weather forecasting enable evacuations to be carried out ahead of tropical cyclone arrival, though the psychological challenges of ‘leaving the safety of one’s own home’ mean that evacuation rates are often low. For tornadoes, warning times are much shorter, providing only enough time for immediate action, such as taking cover in a shelter.

Storms threaten health in multiple ways. The short-term effects on morbidity and mortality are associated with the direct impact of a storm, such as traumatic injuries from being hit by airborne debris or drowning in a storm surge. However, it is also clear that a wide range of other longer-term health impacts are caused indirectly by storms. These can affect a much larger number of people, some of the most significant being exacerbation of existing health conditions from increased stress or the loss of healthcare services due to damages to roads, power supply, or to the health system or facilities themselves; injuries sustained while clearing damage; carbon monoxide poisoning from indoor power generators and cookers used during electrical failures; or respiratory infections among people displaced to emergency shelters. Mental health impacts are also being increasingly recognised. At least in part, these come from the psychological response to the shock of ‘invasion of the home’, especially when the home no longer exists, or takes a long time to be habitable again. These mental health impacts can be of long duration and may return whenever similar conditions threaten. Those particularly at risk are people tied to homes built in unsafe places, and those with limited resources to cope: the poor, women and children, the sick and the aged are disproportionately represented in mortality statistics.

Our collection covers a wide range of papers addressing issues of importance to the health impact of windstorms, with an emphasis on tracking and warning systems, willingness and readiness to evacuate, and the impact of storms on health systems, vulnerable groups, and mental health. We hope that the collection will provide humanitarian practitioners with an easily accessible and accurate evidence base for good practice in emergency planning and response.

Introduction authored by: Professor Brian Golding (Met Office, London, UK) and Dell Saulnier (PhD student at the Department of Public Health Sciences, Karolinska Institutet, Sweden)

[1] https://www.unisdr.org/archive/58911

Photo: Caritas/ CAFOD, November 2013

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