GYX HeatRisk Examination

This study considers HeatRisk, an experimental color-numeric based index developed by the National Weather Service in coordination with the CDC. The purpose of this study was to investigate HeatRisk at all sites in the GYX CWA from 2014-23 and compare it to actual heat headlines that were issued. Annual statistics were tabulated on the difference in HeatRisk days and actual products issued by location for both orange and red HeatRisk days. It was found that according to HeatRisk criteria, the entirety of the GYX CWA is underwarned, particularly in northern locations. However, using HeatRisk as the baseline criteria would lead to a significant increase in heat headlines, causing overwarning across the CWA. Case studies from Summer 2024 heat waves across the CWA were also looked at and compared with HeatRisk days. Additionally, hospitalizations due to heat illness were included from the CDC to show the cumulative effect of heat waves along with acclimation to them through the summer. It was found that using HeatRisk as the criteria for heat headlines is not currently plausible. It remains a possibility that HeatRisk could be modified to become more usable for issuing heat headlines. However, there are many factors involved regarding the impacts of heat across the CWA that should be further investigated.