Addresscloud US Flood

1. What is it?

Addresscloud US Flood (usafld) is a comprehensive, building-level dataset that provides detailed insights into flood-related hazards across the United States. It combines authoritative data sources with Addresscloud’s proprietary enhancements to help insurers assess flood risk with greater precision.

The product integrates FEMA flood zones and Base Flood Elevation (BFE) data, storm surge risk from NOAA, water proximity and elevation data from USGS, and levee protection attributes from USACE. Where FEMA BFE values are not available, Addresscloud interpolates these values using USGS elevation data and offers a distance metric to the nearest surveyed point.

2. How can I use it?

This dataset is valuable for:

• Insurance Underwriting: Evaluate exposure to flooding and price policies accordingly
• Real Estate & Portfolio Risk Analysis: Make informed decisions based on flood exposure and mitigation
• Emergency Planning: Identify high-risk zones for disaster response and preparedness
• Regulatory Compliance: Support planning and building control in accordance with FEMA flood zones and elevation guidance

3. How is the data created?

The Addresscloud US Flood product integrates and enhances data from the following sources:

• FEMA NFHL: Provides flood zone classifications (e.g., AE, VE, X) and Base Flood Elevations
• USGS: Supplies ground elevation (from 1 arc-second and 1/9 arc-second raster grids) and hydrography data (e.g., rivers, lakes via the NHD)
• NOAA SLOSH: Delivers storm surge heights across hurricane categories 1–5
• USACE Levee Inventory: Contributes levee IDs, accreditation status, inspection ratings, and risk classifications
• Addresscloud Interpolation Engine: Where FEMA BFE points are absent, Addresscloud calculates interpolated BFE and proximity metrics using FEMA and USGS inputs

4. Are there any limitations?

• Zonal Limitations: BFE values are only available in zones AE, AH, AO, and VE. BFEs are often spatially sparse.
• Data Currency: Annual updates may result in a lag between current floodplain changes and the dataset. Some BFE surveys are decades old.
• Generalisation: Some USGS and NOAA datasets are regional or raster-based and may not capture micro-geographic variations
• Storm Surge Generality: NOAA’s SLOSH model offers worst-case surge estimates; localised modelling is not included

5. What data points are available?

The Addresscloud US Flood dataset includes the below key attributes. More attributes are available for the individual datasets.

FEMA National Flood Hazard Layer (fenfhl)

• fld_zone: FEMA flood zone designation (e.g., AE, VE, X, etc.)

Base Flood Elevation - BFE (usflod)

• bfe_fema: FEMA surveyed BFE (metres)
• bfe_fema_ft: FEMA surveyed BFE (feet)
• bfe_interp: Interpolated BFE (metres, Addresscloud-derived)
• bfe_interp_ft: Interpolated BFE (feet)
• bfe_dist: Distance to nearest BFE point (metres)
• bfe_dist_ft: Distance to nearest BFE point (feet)

Hydrology & Elevation (usflod)

• elevation: The elevation of the property above sea level in meters
• elevation_ft: The elevation of the property above sea level in feet
• height_above_water: The height of the property above the nearest watercourse in meters
• height_above_water_ft: The height of the property above the nearest watercourse in feet
• ocean_dist: The distance of the property from the nearest ocean in meters
• ocean_dist_ft: The distance of the property from the nearest ocean in feet
• water_dist: The distance of the property from the nearest watercourse in meters
• water_dist_ft: The distance of the property from the nearest watercourse in feet
• water_type: The type of the nearest watercourse
• water_id: The ID of the nearest watercourse

USFS COBRA Zones (uscbrs)

• cobra_area: Indicates if the area falls within Coastal Barrier Resources Act boundaries

FIRM Panel Area (frmpan)

• pcomm: NFIP community participation reference

NOAA Storm Surge (noaslo)

• min_storm_cat: Minimum storm surge height (feet)
• cat_1_height to cat_5_height: Maximum storm surge height for hurricanes categories 1 to 5 (feet).

Addresscloud Watershed Boundaries (usgwbd)

• huc2 to huc12 (in increments of 2): Hydrologic Unit Code from region (huc2) through to subwatershed (huc12)

USACE National Levees Database (usanld)

• levee_id: Unique levee identifier
• levee_status: Accreditation or inspection rating
• levee_risk_class: Indicates water routing and overtopping risk

6. Where can I find out more?

For more detailed information about our US datasets please visit our North America help pages.

For additional information and technical documentation, please refer to the Addresscloud API Documentation.

For support and inquiries, contact Addresscloud through their Help Center.

Due to policy changes in the US not all government sites remain available:

• FEMA National Flood Hazard Layer: https://msc.fema.gov
• NOAA SLOSH: https://www.nhc.noaa.gov/surge/slosh.php
• USGS National Hydrography Dataset: https://www.usgs.gov/national-hydrography