Public warning systems have been around far longer than some might think. They go all the way back to antiquity when the most effective long range warning systems were created by smoke and fire. Soldiers on the beacon towers of the Great Wall of China created smoke in the daytime and fires at night to warn of approaching intruders and to transmit signals.
Today, major technology advancements have created new possibilities for highly effective and far reaching public warning systems.
Before describing the public warning systems in use today, as Benoit Vivier did during our recent webinar, it is important to note that a European Commission defined public warning systems as, “Systems that can alert as many people as possible within a given location about potential or concrete danger and provide them with advice and information on how to react.”
Modern systems
Phone Alerts
The newest addition to public warning systems are mobile phone alerts sent via Short Messaging Service (SMS) or Cell Broadcasting (CB). These are highly effective systems for sending emergency alerts as mobile phones are the most ubiquitous communication tool in the world. SMS alerts can reach 100% of mobile devices at a fast rate. CB alerts are even faster, but are not compatible with 100% of mobile devices.
The most modern versions of mobile alerting include location technology that constantly calculates the number of mobile phones within a crisis-affected area and sends emergency alerts to each phone. Systems can also be customized to send alerts to mobile phones entering danger zones while an emergency situation is still in progress. In the past, emergency response teams often had to allocate personnel based on experience and partial information, which could lead to the misallocation of resources. Using location based technology and depersonalized data,, emergency response teams can now track the movements of those receiving alerts and appropriately allocate resources to ensure crisis-affected populations receive the information and aid they need to stay safe.

Not all countries have access to these highly effective systems, but they are becoming more widespread. By June 2022, modern public warning systems will become mandatory in all EU member states.
Social Media
While social media is another near-ubiquitous communications channel, torrents of content come from dubious sources with misleading or hidden agendas. Governments and public safety agencies are realizing social media’s vast potential to provide officially verified information. Official sites can be used by residents and visitors for accurate and actionable intelligence during disasters and other critical events. Official social media can also be used to counter online misinformation. Recently, the Spanish government released a document aimed at exposing this rampant digital contagion.
Emails
While emails will not reach as many people as quickly as phone alerts, they are an important part of a multi-channel public warning system. Mobile phone alerts are immediate, but if not used properly and with foresight, they can cause panic. Emails are a less intrusive method to disseminate more information and provide crisis-affected populations more time to process critical communications calmly. The use of email by government officials in Belgium to announce COVID-19 confinement notifications helped reduce public panic.
Classic Systems
Sirens
Sirens are perhaps the first thing that comes to mind when people think of public warning systems. While useful, sirens are limited to alerting people of an emergency (or a siren test), but are not capable of providing any information about the nature and location of the emergency, and what actions, if any, people should take to stay safe. Genasys has revolutionized sirens by developing the most advanced voice speaker arrays in the world. Genasys systems transmit both sirens and voice messages with industry-leading vocal clarity and area coverage. Featuring solar power, satellite connectivity and battery backup, Genasys systems continue to operate when power and communications infrastructure is interrupted.
Television & Radio
For many years, government and public safety officials have relied on television and radio to warn and inform populations in danger. Although TV and radio are not as fast as the other public warning channels previously described, they are considered to be the most trustworthy to reassure populations and deliver official information.

Digital Signage
Another emerging public warning channel is digital signage. Critical alerts such as a car accident ahead, wildfires or flooding in the vicinity, or public service announcements, including advising people to stay home during the coronavirus outbreak, are important uses of digital signage that can help keep people safe.
Effective Implementation
Additional public warning system channels are also being implemented. In the Netherlands, ATMs are used to alert people of missing children and can include a picture to help with search.
With several public warning technologies available, strategizing and planning the effective use of each channel will determine how well governments and public safety officials protect at-risk populations. SMS and CB phone alerts have significant advantages over other systems, but each channel is a critical part of a modern public warning system. It is important to have plans which account for variables and contain clear instructions for those deploying emergency alerts. For example, a phone alert informing people of a crisis situation, but not including information and instructions will be far less effective than an alert which includes them. Wrong choices made by panicked populations can create widespread chaos. Emergency warning alerts and instructions must be clear, concise and calming.
The most effective way to ensure public safety during emergencies, disasters and other crises is to utilize multiple public warning channels using informed strategies and plans for every type of critical event scenario. As the effects of climate change, pandemics, political unrest, and natural and manmade disasters continue to increase throughout the world, implementing modern public warning systems is essential to protecting people and at-risk populations.