GLOF early warning: model the water that actually flows
Glacial Lake Outburst Floods are among the most destructive mountain hazards. Yet the metric most agencies still plan against — total lake volume — is not what determines what happens downstream.
The wrong metric
Total lake volume tells you how much water is in the lake. Downstream impact depends on the volume that would actually be released if the moraine breaches — the releasable discharge — and on where that water would travel. Those are different quantities, and planning against the wrong one produces evacuation routes and thresholds built on numbers that can be off by an order of magnitude.
Most current assessments combine empirical area–volume scaling with public 5–30 m DEMs. The result is volume estimates with error bands too wide to plan against, no per-lake change tracking between site visits, and no usable downstream inundation model.
Measure the right quantity
EarthToDate estimates releasable discharge for any glacial lake on Earth, from enhanced 1 m true-colour and 2–4 m multispectral imagery over a globally-validated 1 m BaseDEM (0.5–1 m vertical accuracy). Terrain that accurate is what makes a volumetric estimate — and a downstream flow path — credible.
For each lake it tracks surface extent and volume change from Sentinel-2, models where the discharged water would travel across villages, roads and bridges, raises growth-rate anomaly alerts, and reconstructs a historical baseline from the Sentinel/Landsat archive. Public 30 m DEMs simply cannot support this; commercial DEMs at the required accuracy don't exist as global products.