The proposed trigger: two candidate designs
Multi-source consensus
Each window votes on (station, model) pairs drawn from the five SWALIM gauges that still report, with all three providers competing freely and a station allowed to carry more than one model. Joint basin calibration: 1-in-3.2 overall, 1-in-4.3 / 5.2 per basin. Includes the SWALIM-threshold check, the impact tilt and a no-Google variant.
/trigger/T. Downing · Aug 2026The balanced trigger
The same open multi-model consensus on the five still-reporting gauges, but with the activation probability balanced across basins and seasons as an explicit constraint rather than left to fall out of the search. Seasons come out exactly level; basins within one activation; 7 of 7 severe years and no activation outside the benchmark.
/balanced/design variant · Sep 2026One model per window
Each river-season window runs on a single forecast source rather than a mixture, monitoring all seven reporting-era points and with no threshold below 1-in-3. Google carries Gu, GloFAS v5 carries Deyr; GEOGloWS is an alternative view. Same 1-in-3.2 envelope. Carries twelve review notes behind a toggle.
/trigger-single-model/P. Wairimu · Aug 2026Operations
Live monitoringdaily
Today's status of the trigger: GloFAS and Google Flood Hub forecasts at the seven monitored points read against the four river-season windows, action and readiness legs, point-by-point levels and the daily chart. Updated after the daily run, which starts at 10:00 UTC and waits for the day's forecasts; the same evaluation feeds the email notifications.
/monitoring/status pageGoogle Flood Hub reading
Informational: the latest Google Flood Hub forecast at the seven stations, read against Google's own return-period levels with the trigger's station rule, next to the GloFAS reading the trigger uses. Not part of the trigger.
/monitoring-google/Oct 2026Monitoring replay: Deyr 2023
The live monitoring page re-run on the GloFAS forecasts of October and November 2023, with today's rules and thresholds: the status, map, chart and station tables as they would have read through the 2023 El Niño floods, with the dates the river gauges rose marked alongside.
/monitoring-replay/Oct 2026GloFAS version switch
The Deyr thresholds were fitted on the GloFAS v5 reanalysis, but the operational forecast is still v4 (v4.5 since April 2026; v5 is pre-operational). This page gives the thresholds on each version's own climatology, how far apart they sit, and what the Deyr windows and the envelope look like on the v4 record.
/glofas-version/operational note · Sep 2026Explore the evidence
Mixed models vs one model per window
Both setups on GloFAS and Google only, both on the five reporting gauges, both balanced so each basin-season carries the same activation probability at 1-in-3.2. Two outputs: the year-by-year trigger record, and accuracy (F1, TPR, PPV, lead time) against the gauges and against a target list built from CERF allocations and major EM-DAT years.
/comparison/design delta · Sep 2026Somalia floods analysis: data-source review
Presentation summary of the evidence: SWALIM thresholds, events and crossings, gauge events against flood exposure, model performance on hindsight and forecasts, bias correction, the seven trigger gauges, the grid search, the current best configuration and the envelope decision it implies.
/summary/updated as the analysis movesThe ensemble agreement level
A point counts when the ensemble median crosses its level. This note runs every agreement level from 1 of 11 members to all 11 on the GloFAS v4 reforecast and scores each against the gauge benchmark. No level catches an extra severe year, and no level performs better than the median. Google's archive is a single trace, so the Gu legs have no ensemble to read.
/ensemble-agreement/P. Wairimu · Sep 2026Timing of activations
Dates on which the trigger is met in each season, shown alongside the river gauges and flood exposure in the 14 anticipatory-action districts. One chart per season, Deyr and Gu, with the model discharge, the SWALIM levels against each gauge's own 1-in-3, and the exposure that followed.
/activation-timing/1999–2023, 33 seasonsIndicator explorer
Pick a basin and a year and see how each indicator behaved: the SWALIM gauge record, each source's station-consensus count against its own 1-in-6 thresholds (GEOGloWS included, via its retrospective), and each model's signal at the reference station relative to its own climatology.
/explorer/1999–2023, dailySource material
Analysis notebooksGitHub
The full evidence chain: SWALIM threshold analysis, model-vs-gauge skill, lead-time skill, flood benchmarks, station selection, trigger grid search and the staged-mechanism exploration (notebooks 01–10, P. Wairimu) plus the multi-source mechanism itself (notebook 11).
ds-aa-som-floods/analysisKnowledge-base pageGitHub
The team knowledge-base landing page for this analysis: what was analysed, the headline findings, data sources and how this relates to the (future) Somalia flooding framework.
ds-knowledge-base