The National Heatwave Plan is intended for organisations, healthcare professionals and informal carers. RIVM alerts them when hot weather is expected. That way, they can prepare for the when they give support and care to vulnerable groups. Healthcare organisations, for example, can put their own heatwave plans into action.

Currently, the alerts about the National Heatwave Plan are sent to around 70 nationwide sector organisations and interest groups in the healthcare chain. These nationwide organisations represent groups like the elderly or GPs. The Dutch Red Cross, the Netherlands Municipal Public Health Services and Medical Assistance in Accidents and Disasters and the association of nurses and caregivers in the Netherlands (V&VN) all receive the alerts, too. It is up to the organisations to decide whether and how to inform the people they represent and/or serve.

Three information moments

The National Heatwave Plan describes three moments when RIVM will communicate about heat. The National Heatwave Plan is ‘activated’ only when lasting or extreme heat is very likely.

At the beginning and end of the hot-weather season (by email only)

From May until September, there is a chance of lasting heat that meets the given criteria. This is the period when the National Heatwave Plan may be activated. It is therefore important to be aware of potential heatwaves throughout the entire period.

For this reason, RIVM sends a standard alert to all relevant parties at the beginning of May to remind them that the season has started. This reminder helps organisations and institutions to make timely preparations for a period of lasting heat. For instance, they can review their internal agreements about hot weather and see if these need to be adjusted.

At the end of the season, RIVM sends a final alert to say that the hot-weather season has come to an end. Every time the National Heatwave Plan is activated, there is also an evaluation. The resulting information from KNMI, the Municipal Public Health Services and the organisations involved helps to improve the National Heatwave Plan.

When there is a preliminary alert (by email only)

If there is a chance that there will be a period of four or more days with a maximum temperature higher than 27 °C, KNMI will inform RIVM of this. RIVM will then send an email with this preliminary alert to all relevant parties.

This means that all organisations who receive the email should be aware that there might be a period of lasting heat in the near future. The organisations can carry out whatever internal checks are needed to make sure they are sufficiently able to perform their agreed duties. The exact nature of those duties differs from one organisation (and type of organisation) to another. Every organisation has an individual responsibility to take proper action based on the preliminary alert.

When there is an alert (activation of the National Heatwave Plan)

If there is a high chance that there will be a period of four or more days with a maximum temperature higher than 27 °C, KNMI will consult with RIVM. This meeting will be attended by KNMI’s safety meteorologist and the RIVM coordinator of the National Heatwave Plan. The communication departments of both organisations will coordinate with each other.

Based on this consultation, RIVM will decide whether to send an alert. This decision will take the lasting heat into account, but also other criteria such as the night-time temperature and humidity. If RIVM decides to send an alert, this will activate the National Heatwave Plan. In most cases, this is announced more than 24 hours in advance. RIVM will also publish a news item saying that the National Heatwave Plan has been activated. This news item will also bring the alert to the attention of informal carers and other care providers.

All relevant organisations can use this alert to inform the people they represent and/or serve. Every organisation will decide for itself whether to implement the measures they agreed ahead of time. For example, a care facility could activate its own heatwave plan and a sector organisation could post a message on its website or send a news item to the people they represent and/or serve.

The alert phase includes a tiered information chain.

• RIVM receives information about the weather forecast from KNMI and then decides whether to activate the National Heatwave Plan.
• In consultation with KNMI, RIVM sends a heat alert (by email). This contains both substantive information and the current weather forecast.
• The recipients of this alert decide for themselves how they want to use the information to inform the people they represent and/or serve and their regional contacts. The Municipal Public Health Services, sector organisations and the Dutch Red Cross will also weigh the facts and decide whether to inform the general public through their respective communication channels.
• RIVM and KNMI will publish a joint news item and give information through the website. Often, the activation of the National Heatwave Plan will attract a great deal of attention in the newspapers and on the radio/TV. This makes sure that informal carers and the rest of the Netherlands are informed.
• RIVM sends a daily heat alert (by email) describing the current weather conditions.
• The alert phase concludes with a clear email to all recipients of the heat alert, telling them the date from which the National Heatwave Plan is no longer active. RIVM will also publish a news item on its website.