Summary
The BMJ has published a practical guide for clinicians on preparing for and responding to extreme weather events, which have increased five-fold over the past 50 years. The guide provides a structured approach for assessing patient exposure and vulnerability, maintaining continuity of care during disasters, and supporting recovery afterward.
Weather-related disasters have increased five-fold over the past 50 years, driven by climate change, and the average rise in global surface temperature is heading over 1.5°C, which could result in further rapid and difficult-to-predict hazards. Against this backdrop, The BMJ has published a practical guide for clinicians on preparing for and responding to extreme weather events. The guide, developed by an international group of clinicians and researchers with expertise in disaster medicine, climate and health, primary care, emergency medicine, public health, and health system resilience, acknowledges that the evidence base on extreme weather to inform healthcare is not robust. Disasters are irregular events that disrupt normal systems, including those needed to conduct research, and practices are often based on anecdote, history, and perceptions. A 2025 World Health Organization review of health systems adaptation to climate change noted that "despite recent progress, the field is dominated by descriptive case studies, theoretical frameworks and modelling studies, with no formal tracking or evaluation in place for over 60% of National Adaptation Plans."
The guide offers a structured approach for healthcare professionals to support patients before, during, and after extreme weather events. It frames extreme weather as affecting health directly—through trauma, drowning, burns, heatstroke, hypothermia, and mental health stressors—and indirectly, via secondary hazards such as air pollution, contaminated water, vectorborne disease, damage to crops and livestock, food insecurity, disrupted livelihoods, displacement, and interrupted care. These effects can intensify health inequities, as people face differential degrees of exposure and vulnerability to hazards.
Before an event: assessing hazards, exposure, and patient capacity
The guide recommends that clinicians begin by evaluating community hazards: which extreme weather events have historically affected the region, and how shifting temperature and precipitation patterns might alter those risks. Clinicians should then assess patient exposure—whether a patient lives in a high-risk setting such as a wildfire-prone region with limited egress or a flood plain, or whether their occupation increases exposure.
A central component of the guide is a framework for assessing and improving patient capacity to prepare for and recover from extreme weather events. Drawing from WHO and United Nations wellbeing capital accounting frameworks, the guide suggests evaluating four domains:
- Human health and capability: skills, knowledge, physical and mental health, and ability to respond to an emergency. Clinicians should ask whether the patient has children or other vulnerable people in their care, whether their condition could worsen with exposure to likely hazards or interrupted care, whether they rely on powered medical devices, cold-chain drugs such as insulin, dialysis, or home oxygen, and whether they can receive, comprehend, and respond to early warning systems or evacuation alerts.
- Financial capital: whether the patient has a financial buffer in case their income is affected by a disaster, combined with potential travel, lodging, and supply costs.
- Community relationships: whether the patient lives alone, who comprises their support network, and whether they have people they can count on during a disaster.
- Physical capital: whether the patient's home can cope with likely hazards, including operable windows, air conditioning, air filtration devices, adequate heat, and a backup generator.
The guide advises clinicians to help patients cocreate a multihazard emergency plan and to advise them on what to include in an emergency kit. Suggested kit components include at least 2–3 L of drinking water per person per day for at least 3 days, nonperishable food, prescription and over-the-counter drugs, eyeglasses, hearing aids, phones and chargers, extra cash in small bills, sleeping bags or blankets, essential documents, and paper maps. Clinicians are encouraged to document key risks and plans in the medical record and to consider designing a template for the electronic medical record.
During an event: maintaining continuity of care
During an extreme weather event, the guide advises clinicians to aim to maintain continuity of care while considering their own safety and that of their family and staff. Telemedicine should be considered where possible. If usual services relocate or close, patients may need to be redirected. As a priority, clinicians should manage high-acuity patients and ensure access to essential treatments such as insulin, dialysis, and oxygen.
The guide emphasises understanding chains of health system command and communication, monitoring hazard-specific public early warning systems, and maintaining situational awareness. Observational evaluations from Europe, North America, and Australia suggest that early heat warning systems can reduce mortality related to heat. Clinicians should ask patients about current living conditions—including safety in crowded shelters, tents, or vehicles—access to safe drinking water and food, ability to maintain hygiene, and exposure to smoke or mould, and adapt management and follow-up accordingly.
After an event: supporting recovery and follow-up
Immediately after an event, the healthcare team must ensure that they are physically and psychologically safe to return to work. The guide advises securing the facility with adequate water, electricity, infrastructure integrity, and supplies before resuming operations.
Extreme weather events can have profound short-term and long-term physical and mental health impacts, including injury, death, disruptions to livelihood, and increased rates of depressive and anxiety disorders, suicidality, and substance abuse. The guide recommends that clinicians assess patients for socioeconomic and mental health impacts, ask about missed doses of drugs, missed appointments, and changes in symptoms, and offer drug reconciliation, clinical review, laboratory tests, and repeat referrals where indicated. Open questions about mood, sleep, daily functioning, intimate partner violence, substance abuse, work, and financial stress could be important. Screening tools to assess distress and referral to support where appropriate are also recommended.
Excess morbidity and mortality can persist for many years. Health system and community recovery from an adverse event depends on the strength of the hazard, the capacity of the system, and the extent of exposure. Poor resilience can result in collapse or limited healthcare delivery for months or years. The guide notes that it is possible to learn from experience and transform the health system into one that is better able to anticipate and respond to increasing extreme weather events—for instance by improving heat-related early warning systems, or by using review reports to improve evacuation plans and make the argument for increased resources.
Hazard-specific considerations
The guide provides hazard-specific clinical considerations. For heatwaves, clinicians should be alert for heat rash, heat stress, heat exhaustion, syncope, cramps, and heat stroke, and consider heat-sensitive health conditions including ischaemic heart disease, ischaemic stroke, gastrointestinal disease, genitourinary disease, psychosis, sleep disturbance, anxiety, and depression. For wildfires, smoke is associated with headache, watery eyes, possible decreases in mood, concentration, and sleep, and exacerbates asthma and chronic obstructive pulmonary disease; myocardial infarction and cardiac arrests might become more common. In the medium term, smoke is associated with preterm birth and decreased birth weight. The guide recommends N95 masks, found superior to surgical masks by modelling with respirable fraction deposition of particles for smoke, and notes that a 2016 narrative review concluded portable air cleaners can lower indoor exposure to fine particulate matter and benefit respiratory and cardiovascular health.
For extreme winter weather, clinicians should be alert for hypothermia, frostbite, and increased stroke and heart attack linked to vasoconstriction. For floods and extreme precipitation, the guide warns of increased waterborne and vectorborne diseases such as dengue, malaria, West Nile virus, and vibriosis. For hurricanes, tornadoes, and thunderstorms, clinicians should be prepared to manage trauma, drownings, electrocution, chemical pollution, bioaerosols including mould and endotoxins, carbon monoxide poisoning from indoor generator use, and cholera and typhoid from contaminated water.
The guide also emphasises culturally competent emergency management, noting that groups with histories of marginalisation, forced displacement, or mistrust of institutions can experience a worsening of vulnerability as a result of evacuation to locations with reduced services tailored to their needs and caregivers who are less familiar with these histories.
A case example
The guide illustrates its approach with a case: a 32-year-old patient with a history of childhood asthma presenting with shortness of breath and cough worsened by thick smoke during a severe wildfire season in a remote part of the Canadian subarctic. The patient has scattered expiratory wheezes but no signs of respiratory distress, with O₂ saturation of 94%. The clinician diagnoses an asthma exacerbation triggered by smoke, prescribes two dry powder inhalers—one bronchodilator and one steroid-based—and reviews inhaler use technique, explaining that compared with metered dose inhalers, these devices contribute less greenhouse gas emissions. The clinician and patient together evaluate exposure, assess risk, and identify ways to build capacity. The patient is recommended to wear an N95 mask outdoors during smoky periods and to buy an air filtration device for use at home. The patient leaves with a prescription and an emergency plan, having made arrangements to shop for the components of an emergency kit with a neighbour.