Modernizing Heat Alerts in North Carolina: A Health-Based Framework for Subregional Risk Communication

Abstract

In response to rising extreme heat risks across North Carolina, this study refines and evaluates the North Carolina Division of Public Health (NCDPH) Climate and Health Program’s Heat Health Alert System (HHAS), a health-based warning framework first introduced in 2018. Building on prior development, the authors introduce a new set of season-specific Heat Index thresholds for eight climatologically derived regions, calibrated using historical health outcomes—specifically, emergency department visits and excess mortality records from 2007 to 2022. This comparative analysis shows areas of agreement but also highlights systematic differences, particularly in the timing and sensitivity of warnings. Data used in this report were obtained via the North Carolina Disease Event Tracking and Epidemiologic Collection Tool (NC DETECT), NCDPH’s syndromic surveillance system. NC DETECT is funded by the NCDPH Federal Public Health Emergency Preparedness Grant and managed through collaboration between NCDPH and the UNC-Chapel Hill Department of Emergency Medicine’s Carolina Center for Health Informatics. The NC DETECT Data Oversight Committee is not responsible for the scientific validity or accuracy of methodology, results, statistical analyses, or conclusions presented. This work is supported by the Centers for Disease Control and Prevention Climate-Ready States and Cities Initiative, Building Resilience Against Climate Effects (BRACE) Cooperative Agreement No. 5 NUE1EH001449-03-00.