Since 2011, the CDC has used Census data to help estimate how vulnerable communities are to public health emergencies, including extreme heat. The resulting scoring system, known as the Social Vulnerability Index (SVI), is intended to help local officials plan ahead and respond more effectively during a crisis.
The key part of the SVI is the overall vulnerability score, which is shown below by census tract. A higher score means that the area is relatively more vulnerable. For example, a SVI score of 0.85 means that area is more vulnerable than 85% of all census tracts in NH.