CA Sea Change Atlas

Map Compare tools Side by side County profiles About

Unofficial tool — verify before relying on this for planning decisions.

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Layers

Coastal county boundaries

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County boundaries (27 coastal counties; legal, may include coastal water) Highlight county

Geo / demographic info

Context layers to overlay under any flood layer, each from the agency that publishes the data (EPA, CDC, USGS, NOAA, Caltrans). Click the map to inspect where a popup is available.

People

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Facilities and infrastructure

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Critical facilities (USGS)

Regulated facilities, pollution sources (EPA; zoom in)

Highway traffic counts (Caltrans; zoom in)

Highway truck counts (Caltrans; zoom in)

Land and ecosystems

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BCDC Flood Explorer (Bay Shoreline Flood Explorer)

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Click the map to see values at that point for the layers checked below.

Total water level, MHHW+

36"

Sea level rise

Storm surge

Select a sea level rise and storm surge amount to see the closest matching Total Water Level.

Depth of Flooding

Shoreline Overtopping Disconnected Low-lying Areas Legal Delta boundary

Consequence category, at the current water level

Transportation consequences (highway, truck, and rail traffic) aren't available here. Review them in BCDC's own tool.

East Contra Costa Shoreline Flood Explorer (BCDC / SFEI)

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Click the map to see flood depth and shoreline overtopping at that point. Covers eastern Contra Costa County / the Delta shoreline only (Bay-side flooding is in the group above).

Sea level rise (above MHHW), 0"

Storm event

Depth of Flooding Shoreline Overtopping Disconnected Low-lying Areas

CoSMoS Flood Explorer (USGS Our Coast, Our Future)

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Click the map to see modeled values for the selected scenario, where available.

Show CoSMoS layer Scenario region Scenario topic

Sea Level Rise, 0 cm

Storm Frequency

Cal-Adapt Coastal Inundation (SLR–CIS: CoSMoS & CalFloD3D-TFS)

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Click the map to see whether a point is in each checked model's flood extent. Turn on both models to see where they agree.

CoSMoS (statewide coast, 2 m) CalFloD3D-TFS 5 m (LA, San Diego, SF Bay) CalFloD3D-TFS 50 m (entire coast & Bay) Time period Flood scenario

Sea level rise amounts differ by region and model (CoSMoS: 0–250 cm across the scenarios); see Cal-Adapt's own tool for details.

NOAA Sea Level Rise Viewer

Opacity 100%

Click the map to see whether a point is flooded (connected to the ocean), low-lying but not connected, or neither, at the selected sea level.

Show sea level rise layer

Sea Level Rise, 3 ft

Click the map to see the nearest tide station's high tide flooding thresholds — today's thresholds, not tied to the sea level rise amount above.

High Tide Flooding stations

Interagency Sea Level Scenarios (tide gauges)

Opacity 100%

Click the map to see the nearest tide gauge's projected sea level rise under every scenario. These are values at points, not flood areas.

Projected sea level rise at tide gauges Scenario Year

From the 2022 Interagency Sea Level Rise Technical Report, read live from its Zenodo data. Values can differ from NASA's scenario tool. The first time you turn it on it downloads about 7 MB.

FEMA Flood Zones (National Flood Hazard Layer)

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Click the map to see the FEMA flood zone at that point (neighborhood zoom and closer).

Flood Hazard Zones (effective)

Zoomed in, this shows FEMA's effective flood hazard data only, not including preliminary or pending map updates. Zoomed out, it shows NOAA's older copy as an overview.

NOAA Coastal Flood Exposure Mapper

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Click the map to see which mapped hazards overlap at that point (FEMA zones, high tide flooding, sea level rise, storm surge, tsunami run-up).

Flood hazard overlap

Scales are shown below; click-to-inspect isn't available for this layer.

Hurricane storm surge (Southern California only)

Only Category 1–2 storm surge is mapped, and only for Southern California (San Diego north to around Point Conception) — NOAA's own National Hurricane Center service has no data further north or for higher categories.

High Tide Flooding (CFEM's own layer)

FEMA Flood Zones (CFEM's own layer)

Tsunami run-up areas

CA Sea Change Atlas Map Compare tools County profiles About Licenses Data GitHub

Copyright, data sources & licenses

Flood-depth overlay: live map layers from BCDC's Adapting to Rising Tides Bay Shoreline Flood Explorer — planning-level only, not for parcel-scale, permitting, or engineering use; see their full disclaimer. East Contra Costa flood layers: same BCDC program, from BCDC's East Contra Costa Shoreline Flood Explorer. Coastal inundation scenarios: live tiles from Cal-Adapt's Sea Level Rise – Coastal Inundation Scenarios (CoSMoS and CalFloD3D-TFS). CoSMoS flood extent: live data from USGS CoSMoS / Our Coast, Our Future. Sea level rise and coastal flood exposure layers: live data from NOAA's Sea Level Rise Viewer and Coastal Flood Exposure Mapper. Sea level scenarios at tide gauges: 2022 Interagency Sea Level Rise Technical Report data (CC BY 4.0), read live from Zenodo. County boundaries: live from the U.S. Census Bureau's TIGERweb. Geo / demographic info layers: live data from EPA, CDC/ATSDR, USGS, NOAA C-CAP, and Caltrans (credited on each layer and on the Licenses & sources page). Flood zones: live effective-data-only layer from FEMA's National Flood Hazard Layer — see the layer panel for the effective-vs-preliminary caveat. Zoomed out, an overview from NOAA's older tiled copy of FEMA flood zones is shown instead. Base maps: data © OpenStreetMap contributors; default greyscale style by OpenFreeMap © OpenMapTiles; optional Humanitarian (HOT / OpenStreetMap France) and Esri World Imagery tiles. Address search via OpenStreetMap Nominatim. Full license list: Licenses & sources.