Heat Vulnerability Index

The NY State Department of Health developed Heat Vulnerability Index (HVI) Maps to identify areas in the state where people are vulnerable to heat. Heat vulnerability is how likely a person is to be injured or harmed during periods of hot weather. Vulnerability to heat has been linked to individuals’ characteristics (health status, socio-demographics, etc.) as well as certain aspects of the community where one lives (environment, community demographics). These characteristics or “heat vulnerability factors” can play an important role in one’s ability to adapt to heat.

What is the Heat Vulnerability Index (HVI)?

Although the effects of extreme heat on health can often be prevented, heat-related deaths and illness are common during the summer, especially in vulnerable populations. Since vulnerability to extreme heat in NY State is a growing concern, the NY State Department of Health created the Heat Vulnerability Index (HVI) to help local and state public health officials identify and map heat-vulnerable areas and populations in the state. NY City has its own HVI information.

The HVI can assist in directing adaptation resources based on characteristics of vulnerable populations in that community and can inform long-term heat-mitigation planning efforts in the community. It can help local agencies make decisions to:

  • set up cooling centers in rural and vulnerable areas where many do not have access to air-conditioning at home;
  • provide transportation to and from cooling centers in neighborhoods with higher vulnerability where there may not be public transportation or fewer people own vehicles;
  • include risk communication and alert messaging in multiple languages especially among communities with high proportions of people who do not understand English well;
  • arrange home visits for people in high risk groups like the elderly living alone.

Heat Vulnerability Index Maps

Statewide and county heat vulnerability maps have been developed to display the HVI for each census tract. The HVI was developed based on 13 environmental and socio-demographic heat vulnerability factors identified from previous studies. Census tracts are subdivisions of counties as defined by the US Census Bureau to collect, provide and present statistical data. Census tract level information for these heat vulnerability factors was obtained from the 2006-2010 US Census Bureau American Community Survey (ACS) and 2011 National Land Cover Database (NLCD). The 13 factors were grouped into four categories that represent different aspects of heat vulnerability, which in turn were used to estimate the overall HVI for each census tract. The four heat vulnerability categories include 1) language vulnerability; 2) socio-economic vulnerability; 3) environmental and urban vulnerability; and 4) elderly isolation and elderly vulnerability. More information on the HVI can be found in the article Development of a heat vulnerability index for New York State.

Everyone is at some risk for heat-related illness and during extreme heat events should follow steps to reduce risk. The areas shown on the maps are places where there is a higher proportion of people that have heat vulnerability characteristics. Areas with lower HVI represent places where there is a lower proportion of people that have heat vulnerability characteristics.