Sea level rise GIS data for Hawaiʻi
Hawaiʻi's official sea level rise (SLR) layers are free to view and download. They come from modeling by the University of Hawaiʻi Coastal Geology Group, combined by Tetra Tech, Inc., and are published by the State and by PacIOOS.
Where to view and download
- State of Hawaiʻi Sea Level Rise Viewer (PacIOOS): interactive map of the State layers, with links to download them.
- Hawaiʻi Statewide GIS, Climate MapServer: ArcGIS REST service with every State SLR layer (layers 41–71), also offered as WMS and WFS.
- State open data catalog: each layer has CSV, shapefile, GeoJSON and KML downloads. Example: SLR Exposure Area, 3.2 ft.
- All SLR-XA scenarios in one shapefile (ZIP) from the State GIS download server.
What the State layers show
| Layer | What it is | REST layer (3.2 ft) |
|---|---|---|
| SLR Exposure Area (SLR-XA) | The combined footprint of three chronic hazards: passive flooding, annual high wave flooding and coastal erosion. It's the projected extent of chronic flooding from SLR. | 45 |
| Passive flooding | A modified "bathtub" model of low-lying land below a raised Mean Higher High Water (MHHW) level, including low areas not connected to the ocean (groundwater flooding). Built from lidar-derived elevation models. | 51 |
| Annual high wave flooding | Wave run-up and overwash from the largest wave expected each year (modeled with XBeach from offshore buoy data), as sea level rises. | 55 |
| Coastal erosion | Exposure zone for future erosion on sandy shores, landward from the 2005–2008 vegetation line. There's an 80% probability that erosion stays inside the zone. | 63 |
| Economic loss, flooded highways | Vulnerability layers built from the exposure modeling. | 67 · 71 |
Each layer comes in four scenarios: 0.5, 1.1, 2.0 and 3.2 feet of SLR, based on the upper end of the IPCC AR5 RCP8.5 scenario. RCP8.5 puts 3.2 ft at about the year 2100, but the State's metadata notes that recent observations and projections suggest it could arrive sooner.
Know the limits
- On Hawaiʻi Island, Molokaʻi and Lānaʻi, the SLR-XA is passive flooding only. Wave flooding and erosion were not modeled there.
- Erosion was modeled only for sandy shores of Kauaʻi, Oʻahu and Maui.
- The SLR-XA maps today's landscape. It leaves out future land-use changes and adaptation, storm surge, tsunami, and less frequent big-wave events (for example a 1-in-10-year event).
- FEMA flood maps (FIRMs) are based on historical data and don't include future SLR. For storm-driven flooding with SLR, see the State's 1% Coastal Flood Zone with 3.2 ft SLR layer (summary PDF).
National alternative
NOAA's Sea Level Rise Viewer maps SLR up to 10 feet above average high tides. Hawaiʻi depth rasters (ocean-connected inundation, 0–10 ft above MHHW in half-foot steps, cloud-optimized GeoTIFF, depth in meters) are on the NOAA SLR data download page.
For Honolulu specifically, PacIOOS also hosts a Honolulu Sea Level Rise Inundation Risk viewer.
Background report: the State's Hawaiʻi Sea Level Rise Vulnerability and Adaptation Report (2017) and its 2022 update are hosted on climate.hawaii.gov. TODO: links not added; climate.hawaii.gov blocked automated checks on Oct 23, 2026, so the report pages could not be verified.
These are planning-level maps, not survey-grade, and not a regulatory flood determination.
Sources
- https://www.pacioos.hawaii.edu/shoreline/slr-hawaii/ — checked Oct 23, 2026 (HST)
- https://opendata.hawaii.gov/dataset/slr-exposure-area-3-2-ft-scenario — checked Oct 23, 2026 (HST)
- https://opendata.hawaii.gov/dataset/slr-passive-flooding-3-2-ft-scenario — checked Oct 23, 2026 (HST)
- https://opendata.hawaii.gov/dataset/slr-coastal-erosion-3-2-ft-scenario — checked Oct 23, 2026 (HST)
- https://opendata.hawaii.gov/dataset/1-pct-coastal-flood-zone-with-3-2-ft-sea-level-rise-statewide — checked Oct 23, 2026 (HST)
- https://geodata.hawaii.gov/arcgis/rest/services/Climate/MapServer?f=json — checked Oct 23, 2026 (HST)
- https://prod-histategis.opendata.arcgis.com/datasets/HiStateGIS::slr-exposure-area-3-2-ft-scenario — checked Oct 23, 2026 (HST)
- https://files.hawaii.gov/dbedt/op/gis/data/slr_exposure_area_all.shp.zip — checked Oct 23, 2026 (HST)
- https://geodata.hawaii.gov/arcgis/rest/services/Hazards/MapServer/15 — checked Oct 23, 2026 (HST)
- https://files.hawaii.gov/dbedt/op/gis/data/coastal_flood_zones_summary.pdf — checked Oct 23, 2026 (HST)
- https://coast.noaa.gov/slr/ — checked Oct 23, 2026 (HST)
- https://coast.noaa.gov/slrdata/Depth_Rasters/HI/index.html — checked Oct 23, 2026 (HST)
- https://www.pacioos.hawaii.edu/shoreline/slr-honolulu/ — checked Oct 23, 2026 (HST)