May 10, 2023

Extreme heat events are becoming more severe in Multnomah County. They are happening more often, lasting longer, and growing in intensity. The resulting risk of heat-related illness and death is a serious public health concern for county residents. Multnomah County Environmental Health Services has developed a Heat Vulnerability Index (HVI) to help prioritize and guide extreme heat response and long-term planning. This index builds on similar tools, as well as current literature on the health impacts of extreme heat and climate change.

The index assesses heat vulnerability at the population-level, using three key factors:

  • Sensitivity to heat and illness
  • Exposure to extreme heat and the elements of our built environments which regulate temperature 
  • The capacity to adapt to extreme heat and lessen harm.

The HVI interactive tool displays how heat vulnerability, sensitivity, exposure, and adaptive capacity differ throughout Multnomah County. The tool also includes the 19 indicators used to build the index. By making this tool available to the public, it can be used to help guide long-term investments to reduce heat and short-term response plans during heat events.