US Natural Hazards Index

The first step in disaster preparedness, according to the NCDP Model of Preparedness, is to know your risks. Knowing which hazards exist where you live and work increases your situational understanding to inform and tailor a household, business, or community emergency preparedness plan. In a major upgrade to the beta version of the tool, released in 2016, this second version of the US Natural Hazards Index (NHI v2.0) helps visualize natural hazard data for fourteen hazard types in the United States and Puerto Rico (subject to data availability) at the census tract level. All hazard layers are derived from publicly available data sources. The index was created to provide households, communities, as well as public health and emergency management practitioners an overview of the natural hazards at the US census tract level and to facilitate the comparison of the presence and degree of each hazard along with a summary index score.

Most hazard maps focus on a single disaster type. By creating an aggregated measure from multiple individual hazards, a composite measure of collective hazard can be explored. The multiple hazard index represents the aggregate hazard from fourteen individual hazards, each with a five-class rating displayed as a choropleth map. Each hazard is categorized using a five-class categorization of very low, low, moderate, high, and very high and assigned a value of 1 to 5, respectively. The summative hazard index displays the sum of each layer’s values (e.g., 1-5).

This tool may be used in conjunction with NCDP’s Preparedness Wizard, available in English and Spanish, to begin developing a household emergency plan.

If the application does not load below, or you would like to view it full screen, it may be accessed directly here: Map Application

Use & Interpretation

Hazards exist whether or not they occur in a populated area. Risk maps, in comparison, are a product of vulnerability and the sum of hazard exposure plus exposure potential for economic, infrastructure, and loss of or injury to human life. Some risk maps, such as FEMA’s National Risk Index, also include resilience or a community’s capacity to respond to a disaster as the divisor. Interpretation of this dataset should be made with this distinction.

The aggregated hazard sum score is the topmost layer that can be interacted with through a pop-up at each census tract, which displays each individual hazard rating, the underlying indicator, how to interpret the value, and a description of the source data if the hazard and/or data are present. Users can then toggle through each individual hazard layer to view the five-class categorization of hazard. The map application contains documentation that explains each data source, the value interpretation, and the layer sources, indicators, and geographic coverage.

All efforts were made to include a full data set for the conterminous US, Hawaii, Alaska, and Puerto Rico. However, not all datasets have full coverage. Documentation available in the application contains a table with a geographic coverage reference.

Disclaimers & Limitations

This is a planning tool only and should not be used for response activities. It is recommended to consult with your local emergency management agency for more information on local disaster preparedness and mitigation activities. All datasets included in this map application have their own limitations, and as such, interpretation of the data should be only one piece of information to determine your own personal risk. Personal and local mitigation may reduce your exposure or vulnerability to a hazard, however, this tool does not reflect those efforts.  

It should be noted that at this time, the index score is not adjusted for missing data or the lack of hazard – it is purely summative. Therefore, no data or no hazard receives a zero value in the summative score. Additionally, unlike other hazard indices, the scores are not ranked as the goal is not to make a relative comparison but an objective one to the greatest extent possible. Finally, a hazard that is categorized as very low or low does not mean knowledge of and preparation for that specific hazard should not incorporated into an emergency preparedness plan.

To further emphasize, this tool does not take into account local mitigation, nor does it reflect current or future climate conditions that may alter your hazard exposure. Currently, this tool takes into account 14 hazards, but it does not reflect all possible hazards to communities in the US. Thus, you are encouraged to consult with state and local emergency management agencies for updated local hazard assessments, along with mitigation, preparedness, and response plans that have been designed based on specific local factors.

Acknowledgments

This project was successful due to the contributions from the researchers and subject matter experts who provided the data and background to help build this tool, including: the Columbia Climate School; the Center for International Earth Science Information Network (CIESIN) at Columbia University; Lamont-Doherty Earth Observatory (LDEO) at Columbia University; the International Research Institute for Climate and Society (IRI) at Columbia University; Department of Applied Physics and Applied Mathematics at Columbia University, Colorado State University; University of Nebraska Lincoln; Boston University; Vrije Universiteit Amsterdam; Pyrologix; U.S. Drought Monitor; USDA Forest Service; USGS; NOAA; and UCAR. A very special thanks to AllianceBernstein | AB who supported the refresh initiative.