Terrain-based flood risk screening for any property worldwide. Instant analysis, detailed reports, financial impact estimates — all free.
In July 2021, catastrophic flooding devastated the Ahr Valley in western Germany. The river Ahr, with a catchment of 830 km², surged through the narrow valley with a force not seen since 1804. 134 people died. Much of the affected area had been classified as outside significant flood zones under conventional flood mapping approaches of the time.
TerraFlood's analysis — using terrain modelling, river discharge thresholds, and catchment data — identifies clear warning signals: a major river with an 830 km² catchment running through a confined valley, with the town sitting just metres above channel level. Our model flags this as Moderate Risk — a grade that would trigger elevated insurance premiums, detailed site investigation, and precautionary measures. A moderate risk flag provides an early signal that warrants closer attention, even when other assessments suggest otherwise.
TerraFlood is deliberately conservative — we prioritise avoiding false negatives over inflating risk. A C grade doesn't mean "safe." It means the data shows enough converging risk factors that this location deserves serious attention. TerraFlood aims to surface those signals as early as possible, so that the right questions can be asked before decisions are made.
Why not a higher risk grade? TerraFlood's satellite water layer (JRC Global Surface Water) shows no historical flooding here — because events like the 2021 Ahr flood are too rare and too fast for satellite detection. This is exactly why we built terrain-based flash flood analysis as an independent data layer. The JRC blind spot pulls the score toward C rather than D or E — but the terrain and river signals are clear. We continue to refine our model to better weight catastrophic flash flood indicators.
Try it yourself — analyze any property for free.
30 m global elevation — slope, flow accumulation, valley confinement
Satellite-observed flood history since 1984 — 37 years of occurrence data
ECMWF global river model — real-time discharge and 90-day forecasts
2, 5, 20, 50, 100-year discharge thresholds — flood frequency analysis
D8 flow routing, Topographic Wetness Index, valley width estimation
Named waterways, reservoirs, dams, and coastal features for context
IPCC AR6 sea-level-rise scenarios — SSP1-2.6 through SSP5-8.5 to 2100
Know your flood risk before you buy. Get a clear risk grade and estimated annual flood cost for any address on Earth.
Check any property →Price flood policies with confidence. Property-level Expected Annual Loss calculation with customizable parameters, return period analysis, and climate projections.
Screen sites for flood exposure before you invest. Batch analysis, 3D terrain visualization, and detailed PDF reports for due diligence.
Start free trial →Powered by seven independent data sources. See exactly what's driving the risk with transparent sub-scores for terrain, river exposure, water history, and slope — with no black box.
| Return period | Flood depth | Loss |
|---|---|---|
| 2-year | 0.4 m | €8,200 |
| 5-year | 0.8 m | €28,400 |
| 20-year | 1.4 m | €74,000 |
| 100-year | 2.1 m | €138,000 |
Expected Annual Loss calculator customizable for property value, building type, flood defenses, floor height, and climate scenario projections through 2050 and beyond.
Download branded PDF reports for your files. Explore flood risk in interactive 3D terrain visualization. Export and share with clients, lenders, or underwriters — all from the browser.
TerraFlood is a flood risk screening tool. It uses satellite-derived terrain data, global river discharge models, and historical water occurrence data to provide indicative flood risk estimates at any location worldwide.
It is designed to flag locations that warrant further investigation — not to replace professional, site-specific flood risk assessments.
Our model is deliberately conservative. It may underestimate risk in locations where extreme events exceed historical statistical benchmarks (as in the 2021 Ahr Valley flood, where actual discharge was six times the modelled 100-year level). It may also overestimate risk in locations protected by flood defense infrastructure not captured in our datasets.
For property transactions, insurance underwriting, or construction planning, we recommend using TerraFlood as a first-pass screening tool alongside consultation with qualified local professionals.
Every feature, for every user, with no account required.
We built TerraFlood to make flood risk information more accessible. The consumer tool is free and open to everyone. We sustain development through our enterprise API — used by insurers, property platforms, and developers who need bulk access or custom integrations. If that sounds like you, see below.
Need bulk access or a custom integration? Our REST API delivers flood risk data at scale.
Contact us to discuss pricing and onboarding.
enterprise@terraflood.com →Data sourced from Copernicus, ECMWF, and JRC · Built in Vienna, Austria