Hazard Metrics
The Resilience Insights layers include different types of hazard exposure metrics, the use of which depends on the geography type of the asset or area being analyzed (for example, a site, line, or area), and the type of hazard. Variations include probabilities of hazard exposure relative to given severity thresholds, as well as binary exposure indicators relative to given severity and probability thresholds.
Exposure metrics are also provided for community attributes, such as population and property value, within areas of analysis. See Hazard Probabilities and Community Attribute Exposures for an explanation of the available metrics and the Supported Hazard Metrics table for details.
Hazard Probabilities
Typically, each hazard that we support has field-specific standards and reporting definitions. For instance, FEMA reports the 1% or 100-year return period floodplain, USGS reports the 2% in 50-year peak ground acceleration, and NOAA reports return periods for hurricanes of different categories. While these definitions are suitable for their respective hazards, the lack of consistency can be confusing when presented together. To address this confusion, where possible, we've standardized our hazard definitions by providing probabilities on standard severity thresholds. Furthermore, by providing multiple severity thresholds, you can get a more quantitative understanding of their risk.
Parcel and Census Aggregation
For most hazards, we provide probability metrics at the parcel level and aggregate them at each supported census geography. At the parcel level, we report the worst value per hazard. For metrics at census aggregation levels or for custom areas, we use the non-area weighted estimated average for the areas where we have coverage. In other words, we report the estimated average probability (daily, monthly, or annually) across the specific geography. Probabilities should return metrics ranging from 0-1; a reported value of 0 indicates a 0 probability of the supported hazard for that specific area.
The exceptions include inland floods and FEMA floods, in which we indicate whether the parcel is in a 100-year floodplain, and sea level rise, which reports the inundation depth based on depths of sea level rise. For these hazards, because we don't report probabilities, we also don't aggregate to the census geography.
If a specific hazard is not supported for a location, such as coastal flooding on the West Coast, we report the values as null.
Community Attribute Exposures
For all census geographies we report the exposure of community attributes, such as population, jobs, assessed value, or land area, to each hazard. Community exposures are calculated by multiplying the count or amount of a community attribute by the hazard probability at the parcel level, then summing over broader areas.
Supported Hazard Metrics
Hazard | Parcel | Census Aggregation | Community Exposure |
|---|---|---|---|
Flood Hazards | |||
Indication of whether the parcel is in a 100-year flood zone, based on the extension of the FEMA flood zone | Not available | Percent of community attribute exposed to 100-year flood zone, based on the extension of the FEMA flood zone | |
Identifies the FEMA flood zone value | Not available | Percent of community attribute exposed to FEMA 100-year flood zone | |
Annual probability of coastal flood inundation depth of:
| Estimated average annual probability of coastal flood inundation depth of:
| Annualized community attribute exposed to coastal flood inundation of:
| |
Inundation depth given a sea level rise of:
| Not available | Percent of community attributeexposed to:
| |
Extreme Heat & Precipitation Hazards | |||
Annual probability of wildfire with flame length of:
| Estimated average annual probability of wildfire with flame length of:
| Annualized community attribute exposed to wildfire with flame length of:
| |
Monthly probability of drought severity at or exceeding:
| Estimated average monthly probability of drought severity at or exceeding:
| Monthly community attribute exposed to drought severity at or exceeding:
| |
Daily probability of maximum temperatures at or exceeding:
| Estimated average daily probability of maximum temperatures at or exceeding:
| Daily community attribute exposed to maximum temperatures at or exceeding:
| |
Daily probability of maximum precipitation totals at or exceeding:
| Estimated average daily probability of maximum precipitation totals at or exceeding:
| Daily community attribute exposed to maximum precipitation totals at or exceeding:
| |
Wind Hazards | |||
Annual probability of hurricane winds at or exceeding these categories:
| Estimated average annual probability of hurricane winds at or exceeding these categories:
| Annualized community attribute exposed to hurricane winds at or exceeding these categories:
| |
Annual probability that a given location is impacted by tornado winds at or exceeding:
| Estimated annual probability that a given location is impacted by tornado winds at or exceeding:
| Annualized community attribute exposed to tornado winds at or exceeding:
| |
Annual probability of strong winds at or exceeding these speeds:
| Estimated average annual probability of strong winds at or exceeding these speeds:
| Annualized community attribute exposed to strong winds at or exceeding these speeds:
| |
Geological Hazards | |||
Annual probability of peak ground acceleration (PGA) at or exceeding:
| Estimated average annual probability of peak ground acceleration (PGA) at or exceeding:
| Annualized community attribute exposed to peak ground acceleration (PGA) at or exceeding:
| |