About CAP
CAP provides a standardized digital format for alerts that can be used across all technologies. This interoperability allows a single CAP message to activate multiple alerting systems simultaneously at low costs. It also supports multilingual communication and ensures accessibility for people with special needs. Speed is crucial in emergency situations, and CAP ensures that warnings reach people quickly, which is especially important for sudden-onset hazards such as earthquakes, tsunamis, and tropical cyclones.
By enabling alerts to be delivered through multiple channels, CAP enhances public safety by reducing confusion and improving response efficiency. It is also designed to work with modern communication technologies, including mobile alerts, digital signage, social media, and home alarm systems. Moreover, CAP-based systems provide emergency managers with a comprehensive operational picture, allowing them to compile alerts from various sources and make informed decisions.
CAP and Early Warnings for All
CAP and Impact-based forecast and warning services (IBFWS) are two complementary approaches that enhance the effectiveness of early warning systems under the Early Warnings for All (EW4All) initiative.
CAP caters to all types of emergencies and is designed for all media and all hazards, reaching everyone. CAP alerts are issued by designated authorities and transmitted via the WMO Register of Alerting Authorities (WMO-RAA), which validates the authenticity of alerting entities. Today, with a proliferation of information channels including digital platforms and social media, it is essential to ensure that warnings originate from trusted sources. The WMO-RAA supports this by maintaining a registry of authorized institutions, thereby promoting confidence in official warnings and mitigating the risk of misinformation.
These validated CAP messages are aggregated and displayed through the Severe Weather Information Centre (SWIC), which enhances access to warnings related to high-impact weather, water, and climate events issued by WMO Members.
While CAP focuses on the format and authenticity of warnings, IBFWS emphasizes its content and relevance. It shifts the focus from forecasting what the weather will be to what the weather will do. This approach enables actionable, user-centred warnings that help protect lives, property, and livelihoods.
Together, CAP, IBFWS, the WMO-RAA and SWIC contribute to the Global Multi-hazard Alert System (GMAS) - WMO’s coordinated framework to strengthen the availability and quality of authoritative alerts on weather, water, and climate hazards at regional and global scales. GMAS leverages and supports national early warning systems and promotes their long-term sustainability. As a foundational mechanism of the EW4All initiative, GMAS ensures that no one is left behind when hazards strike.
WMO works closely with National Meteorological and Hydrological Services (NMHSs) and key stakeholders, including the International Federation of Red Cross and Red Crescent Societies (IFRC), International Telecommunication Union (ITU), MeteoAlarm and AlertHub.org to enhance global CAP implementation.