Overview

• Demo messages with a loud tone reached residents in 28 cities across seven northern states on Saturday afternoon, startling many and prompting viral posts.
• The system uses Cell Broadcast to deliver on-screen warnings to all compatible phones in mapped risk areas without registration, including when devices are on silent.
• Officials cited compatibility limits focused on newer Android models (from 2020) on 4G or 5G networks, and reports noted uneven delivery times and missed alerts.
• State defense agencies issue messages after federal authorization, and the tool defines two levels of urgency: Extremo for immediate danger and Severo for near-term risk.
• Amapá will expand to statewide alerts starting September 24, with additional tests in the Center-West on September 27 and a regional rollout slated for October 1.