What is a heatwave?
In the UK, a heatwave is declared when temperatures meet a set threshold for 3 or more consecutive days. However, different counties have different thresholds. In Hampshire the temperature threshold is 27 degrees Centigrade, and the Isle of Wight is 26 degrees Centigrade.
These thresholds are calculated by the Met Office and are based on the maximum temperatures at the mid-point of summer (15th July). These thresholds have risen over the years as temperatures generally rise around the globe.
Heatwaves are most common in the summer months when high pressure develops over an area. These weather systems are slow moving and can stay in place for several days or weeks.
Local Risk Rating
Very high
What does the Local Resilience Forum do to prepare for heatwaves?
We are not able to prevent heatwaves however through better forecasting and advanced warning we can better plan for when they occur.
The Local Resilience Forum has well tested arrangements in place to assess the situation and prepare for heatwave impacts across Hampshire and the Isle of Wight. We work with organisations and key stakeholders to ensure that they are undertaking their appropriate actions during a heatwave.
The UK Health Security Agency (UKHSA) have published an adverse weather and health plan which promotes preparedness and all year planning for heatwaves. Part of this plan is a Heat-health Alert system that is used between 1 June – 30 September every year. The service is aimed at health and social care professionals and anyone with a role in reducing health impacts caused by extended periods of hot weather. For individuals receiving the service, it also provides situational awareness if health and well-being is at risk, allowing precautions to be taken. Click the button below to find out more.
UKHSA Adverse Weather and Health Plan
During periods of prolonged heatwave additional measures may be put in place to support communities, education settings and health and social care providers. This includes providing key information on how to safely operate and stay cool through warning and informing.
Associated Risks
A heatwave could have health impacts to the general population. Disruption to transport networks, supply chains, power supplies and water supplies could happen. Social and economic disruption would be likely as everyday behaviours have to change, including working patterns and levels of productivity. Other hazards are very likely to occur, including flooding from severe thunderstorms, poor air quality, drought, and wildfires.
Further information on some examples of further risks that could occur during a heatwave is available below:
- Surface Water Flooding
- Land Movement
- Poor Air Quality
- Wildfire
- Water Infrastructure – Failure or loss of Drinking Water
- Drought
How can you prepare for a heatwave?
1. Before a Heatwave
As a member of the public, you can access and sign up to weather warnings for your area including Extreme Heat warnings. You can sign up to receive these warnings by email via the following link:
Or there is a Met Office App available via the app store or google store that will provide you with up-to-date information on weather warnings (including Extreme Heat)
2. During a Heatwave
During extended periods of hot weather, people and animals are at risk. To reduce the risks, the following should be considered:
Apply high-factor sunscreen regularly during the day
Try to keep your house cool; closing blinds and curtains can help
At night, keep your sleeping area well ventilated
Take cool (not cold) showers or baths or spray yourself with water throughout the day.
Wear lightweight, loose, light-coloured clothing and a wide-brimmed hat
Drink plenty of cold fluids, but not alcohol or caffeine, which dehydrate the body
If driving, keep your vehicle ventilated to avoid drowsiness. Take regular breaks and have plenty of water in the vehicle
Try to avoid going out during the hottest part of the day (11.00am - 3.00pm)
Avoid being in the sun for long periods of time
The elderly and very young are most at risk for dehydration. If you have elderly neighbours check on them daily
Avoid excessive physical activity (it can cause heat stroke or heat exhaustion) or do it in the cooler ends of the day
Ensure that babies, children, elderly people or animals are not left alone in stationary cars
