Heat-Health Alerting system
The Heat-Health Alerting system is part of the Weather-Health Alerting system, which is operated by UKHSA in partnership with the Met Office. This is part of the alerts and warnings section of the hazard: heat.
Applies to England
CCHS navigation menu:
CCHS homepage
Topic: climate-related hazards
Hazard: all climate-related hazards, heat
Key resources for Heat-Health Alerting (HHA) system:
- Summary - HHA system
- HHA system - voluntary and community sector (action card)
- HHA system - commissioners (action card)
- HHA system - health and social care providers (action card)
- HHA system - national government (action card)
More content:
Summary
The Heat-Health Alerting (HHA) system is part of the Weather-Health Alerting (WHA) system. A full description of the alerting system can be found in the link above. Impact-based HHA warning systems have been developed alongside the Adverse Weather and Health Plan.
The alerts are aimed at professionals within the health and social care sector, those who have a role in responding to hot weather, and are freely available to be accessed by the public. Make sure you are registered to receive the alerts directly by email by completing the registration form.
HHA are issued when hot weather is forecast that could lead to impacts on health within the population of England. The core HHA seasons runs from 1 June to 30 September each year. However, should an episode of heat occur outside of this core period, an extraordinary alert will be issued. Within the core alerting period, heat-health planners are also issued every Monday and Friday to provide weather-health horizon scanning for the following 5 days, 6 to 15 days, and 16 to 30 days.
During the summer, the UK Health Security Agency (UKHSA) and the Met Office monitor the weather forecasts and where episodes of hot weather are identified a joint dynamic risk assessment is carried out and the appropriate alert issued. More detail is available within the Weather-Health Alerts System user guide.
Since 2023, the HHAs transitioned to impact-based alerting, and have provided professionals with information on the impacts likely to be observed as a result of the hot weather. Impact-based alerting allows professionals to understand the likely impacts and make informed decisions about actions they should take.
The alerts are given a colour (yellow, amber or red) based on the combination of the impact the weather conditions could have, and the likelihood of those impacts being realised. These assessments are made in partnership with the Met Office when adverse weather conditions are indicated within the forecast.
Figure 1. Heat-Health Alerting system
The system aims to cover the spectrum of action from different groups. In general terms these are:
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Green (preparedness) – no alert is issued as the conditions are likely to have minimal impact on health; business as usual; summer planning and preparedness activities
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Yellow (response) – these alerts cover a range of situations; yellow alerts may be issued during periods of heat that would be unlikely to impact most people but could impact those who are particularly vulnerable; or when the confidence is low that forecast conditions may lead to more significant impacts
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Amber (enhanced response) – an amber alert indicates that weather impacts are likely to be felt across the whole health service, with potential for the whole population to be at risk; non-health sectors may also start to observe impacts and a more significant coordinated response may be required
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Red (emergency response) – a red alert indicates significant risk to life for even the healthy population
In England there are 2 early warning systems related to high temperature: HHA and the extreme heat (EH) warnings as part of the National Severe Weather Warning Service (NSWWS) operated by the Met Office. Each system has a slightly different target audience yet work together to help focus the messages being transmitted. Full details of how they are aligned can be found in the user guide.
UKHSA has also developed the Adverse Weather and Health Plan (AWHP) action cards containing a list of potential actions that organisations and responders should consider that are aligned with the yellow, amber and red alerts that could be used during a heat event, and are available above.