SRG · Physics
Storm Surge
GTSM hydrodynamic storm-tide return levels (COAST-RP) on DeltaDTM bare-earth elevation; tropical from the STORM 10,000-year synthetic catalog, extratropical from ERA5, de-duplicated at event level against IBTrACS · v0.1 · 2026-09
US Gulf Coast — the Katrina 2005 calibration coast
Coastal storm-surge screening from a hydrodynamic solve, so wind direction, fetch, basin geometry and tide-surge interaction are inside the numbers rather than approximated. Still-water only — no wave setup or runup — on a frozen 1980-2017 climatology with no sea-level rise, and flood defences are not modelled, so below-datum land reads as undefended. Screening for portfolio triage, not engineering design.
What ships
Surfaces — P(inundation) at 50 / 250 / 500-year horizons (500-year default) with a five-class cut, uncertainty and coverage. Returns — still-water inundation depth in metres at rp50/100/250/500, on the same return-period grid as Hurricane so wind and surge combine return-for-return.
Every release: 0–1 score · 5-class band · per-pixel uncertainty · input-coverage mask · STAC item · methodology doc.
Inputs
COAST-RP storm-tide return levels (Dullaart 2021), DeltaDTM v1.1 bare-earth elevation (Pronk 2024, from Copernicus WorldDEM-30), STORM synthetic cyclone catalog, ERA5, IBTrACS
Version history
What changed between releases — the same notes that ship with the data. Newest first.
Surfaces
v0.1
2026-08
current
- Both storm populations, counted once. Tropical surge from the STORM 10,000-year synthetic cyclone catalog and extratropical surge (North Sea, nor'easters, Baltic, Mediterranean) from ERA5 — de-duplicated at the event level, so hybrid storms like Sandy are counted exactly once.
- Hydrodynamic source physics. Built on the GTSM global tide-and-surge solve (COAST-RP): wind direction — including negative surge on offshore-wind coasts — fetch, basin geometry and tide–surge interaction are inside the numbers, not approximated.
- Petrel coastal amplification. A tropical-branch enclosure amplification calibrated on Typhoon Haiyan (Tacloban) and Hurricane Katrina (Mississippi coast) closes the sub-grid gap where compact intense storms meet semi-enclosed shallow bays.
- Consistent with Petrel hurricane wind. Same underlying cyclone catalog — wind and surge losses can be combined without event-set mismatch.
- Surfaces: 50/250/500-yr inundation probability, 500-yr depth, 5-class exposure banding, uncertainty, coverage.
- Documented exclusions: wave setup, sea-level rise, flood defences (below-datum land reads as undefended), extratropical-transition surge.
Returns
v0.1
2026-08
current
- Depth, not just probability. On low-lying deltas the probability of flooding within 500 years is effectively 1.0 everywhere — true, but it cannot tell a 2 m pixel from an 8 m one. This line carries the physical depth that drives damage.
- Consistent with Petrel hurricane wind. Both products are driven by the same STORM synthetic cyclone catalog, so wind and surge combine return-for-return without event-set mismatch.
- Both storm populations, counted once. Tropical surge from synthetic cyclones and extratropical surge (North Sea, nor'easters, Baltic, Mediterranean) from reanalysis, de-duplicated at the event level.
- Hydrodynamic source physics. Wind direction — including negative surge on offshore-wind coasts — fetch, basin geometry and tide–surge interaction come from a global tide-and-surge solve, not a parametric approximation.
- Elevation-bounded domain. The scored band follows terrain and hydrology rather than a fixed distance from shore, so it extends far up flat deltas and stops quickly on steep coasts.
- Documented exclusions: wave setup, sea-level rise, flood defences (below-datum land reads as undefended), compound rainfall/fluvial flooding, extratropical-transition surge.
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