Extreme Heat Risk Levels Highlighted in Phoenix Area
The National Weather Service (NWS) in Phoenix has issued guidance on the HeatRisk system, which categorizes heat conditions from Level 0 (no risk) to Level 4 (extreme risk). This system is designed to provide a quick overview of heat-related risks over a seven-day period. During extreme heat events, alerts such as Extreme Heat Watches and Warnings are issued. These alerts are based on temperature thresholds, duration of heat, and humidity levels. For example, Phoenix Sky Harbor Airport has recorded yearly counts of extreme temperatures, with 110°F (43.3°C) days being a common occurrence. The NWS emphasizes that heat is the deadliest weather hazard in Arizona, with heat-related illnesses occurring even on days with lower risk levels. (Source: NWS Phoenix Heat Page, Source time: not specified) 
