Thresholds
Admin console. Configure per-hazard/indicator alert thresholds and the ResponseProtocol that auto-attaches when an alert opens — moved under Early Warning since thresholds are what trigger it. The standing Risk baseline is sourced here and read at Risk Assessments & Maps (DD-150). Registered hazards and layers are managed at Admin → Data Registry & Sources; this screen only configures what triggers on them.
What makes up a threshold
The same shape has to hold a drought index, a river return period and a wind speed. These are fields on the threshold row, configured per hazard — not code.
| Field | Why it is part of the threshold |
|---|---|
| Indicator or forecast source | Both are evaluable and both are edited identically — an alert may be triggered from a forecast value, not only from an observed one (FR-18). |
| Accumulation / reference period | Part of the threshold's identity, not a display detail. SPI-3 ≤ −1 and SPI-12 ≤ −1 mean different things; an SPI threshold saved without its accumulation period is not interpretable and must not be saveable. Same rule for a heat threshold's percentile baseline and a flood threshold's return period. |
| Confirmation / persistence rule | How many consecutive evaluation cycles must agree before escalation. Drought escalates only after 2 consecutive monthly cycles; a rapid-onset hazard confirms on the next forecast cycle. A configured number of cycles, not a code branch. |
| Recovery class | Whether a brief return above the value holds the alert or resolves it. Without this the status oscillates in and out of breach every time an index crosses back for one cycle. |
| Severity | Watch / Warning / Severe only — fixed vocabulary, fixed colours, never free text (FR-19A). The same value the map legend and report text cite (FR-27). |
Severity cap at long lead. A top-level classification issued beyond about 3 days is capped one level down, following GDACS practice, so forecast uncertainty at long lead does not produce false-alarm churn. Configured per hazard as a lead-time boundary.
Filter
Layers are registered once at Data Registry & Boundaries; this filter only scopes which registered layer's threshold configuration is shown below.
Thresholds — Flood Layer: Ikopa gauge / river level (m)
| Enabled | Indicator | Accumulation / reference | Operator | Value | Severity | Source | Verification | |
|---|---|---|---|---|---|---|---|---|
| River level (Ikopa gauge) | 2-year return period | ≥ | 4.2 m | Watch | Indicator | Verified | ||
| River level (Ikopa gauge) | 5-year return period | ≥ | 5.0 m | Warning | Indicator | Verified | ||
| GloFAS 3-day forecast level | 5-year return period, ≥30% ensemble exceedance | ≥ | 5.0 m | Warning | Forecast | Verified | ||
| River level (Ikopa gauge) | 20-year return period | ≥ | 6.0 m → 4.8 m (proposed) | Severe | Indicator | Pending verification |
Thresholds — Cyclone Layer: Track model / wind gust (km/h)
| Enabled | Indicator | Accumulation / reference | Operator | Value | Severity | Source | Verification | |
|---|---|---|---|---|---|---|---|---|
| Sustained wind (10-min mean) | 48 h before onset of 34 kt winds — conditions possible | ≥ | 34 kt (63 km/h) | Watch | Forecast | Verified | ||
| Sustained wind (10-min mean) | 36 h before onset of 34 kt winds — conditions expected | ≥ | 48 kt (89 km/h) | Warning | Forecast | Verified | ||
| Sustained wind (10-min mean) | 36 h before onset — conditions expected | ≥ | 64 kt (118 km/h) | Severe | Forecast | Verified |
Severity cap: beyond 3 days lead, a Severe classification is capped one level down to Warning. Scale and lead-time conditions from the SWIO Tropical Cyclone Operational Plan (WMO-No. 1178); 48 h / 36 h watch and warning definitions per standard practice.
Thresholds — Drought Slow-onset · bulletin workflow, never the alert surface
Staged threshold — each severity adds a condition to the one below it. Values here are entered as configuration defaults, not constants: the single value is −1 standard deviation, applied identically to SPI-3, zSM and zFAPAR (Copernicus Combined Drought Indicator, three-stage scheme).
| Enabled | Indicator | Accumulation / reference | Operator | Value | Severity | Source | Verification | ||
|---|---|---|---|---|---|---|---|---|---|
| SPI | 3-month required | ≤ | −1.0 | Watch | Indicator | Verified | |||
| SPI (alternative entry condition) | 1-month required | ≤ | −2.0 | Watch | Indicator | Verified | |||
| Soil moisture anomaly (zSM) — and Watch already met | Standardised anomaly, dekadal | ≤ | −1.0 | Warning | Indicator | Verified | |||
| FAPAR anomaly (zFAPAR) — and Warning already met | Standardised anomaly, dekadal | ≤ | −1.0 | Severe | Indicator | Verified | |||
| Seasonal precipitation outlook | Departure from climatology, 1–6 months lead | ≤ | readiness value | Watch | Forecast | Pending verification |
Confirmation and recovery rules — Drought
Configured per hazard, on the threshold set — not code.
| Recovery condition | Class | Effect |
|---|---|---|
| zSM returns to between −1.0 and 0.0 after a drought episode | Hold | Alert stays open — does not close |
| zFAPAR returns to between −1.0 and 0.0 after a drought episode | Hold | Alert stays open — does not close |
| Both precipitation and vegetation back to normal | Resolve | Alert resolves; verification becomes available |
Basis: Copernicus EDO/GDO Combined Drought Indicator factsheets v3/v4 · WMO-No. 1090 (SPI User Guide) · two-cycle persistence after Domingues et al., NHESS 24, 4661–4681 (2024).
Reference values for configuration — other hazards
These are defaults to enter as configuration when a hazard is onboarded, never constants in code. Each is taken from a published methodology, named in the Basis column, and must be locally recalibrated before it triggers anything.
| Hazard | Watch | Warning | Severe | Basis |
|---|---|---|---|---|
| Drought | SPI-3 ≤ −1 (or SPI-1 ≤ −2) | above and zSM ≤ −1 | above and zFAPAR ≤ −1 | Copernicus CDI, three-stage |
| Flood (riverine) | 2-year return period | 5-year | 20-year | GloFAS, raised at ≥30% ensemble exceedance |
| Cyclone | Moderate tropical storm 34–47 kt | Severe tropical storm 48–63 kt | Tropical cyclone ≥64 kt | SWIO scale, RSMC La Réunion (WMO-No. 1178) |
| Wildfire | FWI 21.3–38.0 | 38.0–50.0 | >50.0 | GWIS/EFFIS — calibrated for Europe, recalibrate locally before triggering |
| Heatwave | No transferable numeric value exists. Configured form: percentile of local daily climatology (commonly 90th/95th), on both daily maximum and minimum temperature, sustained a minimum number of consecutive days, over a 30-year baseline. | WMO-No. 1142 — health-based, locality-specific | ||
| Earthquake activation tier only | PAGER Yellow | PAGER Orange | PAGER Red | USGS PAGER — post-event only, no readiness tier possible |
| Flash flood | Local guidance value per basin | Local guidance value per basin | Local guidance value per basin | GPM IMERG + locally derived flash-flood guidance; values must be calibrated per basin |
| Landslide | Configured intensity-duration threshold | Configured intensity-duration threshold | Configured intensity-duration threshold | NASA LHASA / national inventory; local derivation required before activation |
| Coastal flood | Configured surge/level threshold | Configured surge/level threshold | Configured surge/level threshold | Storm surge, tide and coastal DEM; national calibration required |
| Tsunami | External warning product | External warning product | External warning product | IOC/UNESCO IOTWMS; externally supplied severity, not recomputed by MHEWS |
Cyclone and earthquake severity may be supplied by the responsible authority and shown with attribution. MHEWS does not recompute an authority-declared severity. Where an event has less than six hours of lead time, the alert record is visibly flagged as very short lead time and the applicable approved response protocol is shown; this screen does not invent a bypass rule that is not defined in the requirements.
ResponseProtocol — Flood / Warning
Checked chips (Agriculture, Water) are the sectors this Flood/Warning protocol targets; selecting/deselecting a chip is illustrative only in this static mockup.
| Sector | Action | Notify |
|---|---|---|
| Agriculture | Advise farmers to move stored produce/livestock to higher ground; suspend irrigation releases upstream. | District Agriculture Office, Farmer distribution list |
| Water | Check pumping-station intake levels; prepare to shut down low-lying intakes. | Water utility operations desk |
| Health | Pre-position water-purification supplies at district clinics in flood-prone communes. | District Health Office |
| General | Standard public-safety guidance (avoid river crossings, monitor local radio). | District Preparedness Group, Farmer/public feed |
- Confirm gauge reading against GloFAS forecast
- Check Risk/Impact estimate for affected districts
- Draft or review narrative
- Route to release authority
For slow-onset hazards, record the evaluation period explicitly, for example: monthly cycle, confirmation after 2 consecutive cycles.
Risk baseline — sourcing
One setting per hazard. Which mode is in use is carried through to every screen that reads the baseline, because what the platform may claim differs by mode.
| Hazard | Sourcing mode | Source | Scope | Last updated | |
|---|---|---|---|---|---|
| Flood | Mode A · Supplied | INFORM Subnational Risk Index (L-19) | All regions | 2026-05-01 | |
| Cyclone | Mode A · Supplied | INFORM Subnational Risk Index (L-19) | All regions | 2026-05-01 | |
| Drought | Mode B · Computed | Hazard history × exposure × vulnerability × capacity, configured weights | Grand Sud districts | 2026-04-15 | |
| Earthquake | Mode C · Absent | — | — | — |
Mode C is a valid configuration, not a failure. Where no baseline exists the platform falls back to exposure-only reporting: exposed counts, no claim about consequence. Warnings still function; the risk-context panel is simply omitted.
ResponseProtocol coverage by hazard
Configure one protocol per hazard, severity and applicable timeframe. Slow-onset protocols state the evaluation period, such as monthly cycle and two-cycle confirmation.
| Hazard | Severity | Applicable timeframe | Protocol source | Status |
|---|---|---|---|---|
| Drought | Watch / Warning / Severe | Monthly cycle; confirm after 2 consecutive cycles | Configured | |
| Flood | Watch / Warning / Severe | Each forecast cycle; operational horizon +3 days | Configured | |
| Cyclone | Watch / Warning / Severe | Season Nov–Apr; each bulletin and forecast cycle | Review needed | |
| Wildfire | Watch / Warning / Severe | Daily FWI evaluation and per detection update | Not configured | |
| Heatwave | Watch / Warning / Severe | Consecutive-day threshold; health-sector review period | Not configured | |
| Earthquake / Tsunami | External product / post-event | Per event; no forecast period where none exists | Not configured |
Versioning & audit
| Version | Threshold | Change | Actor | When |
|---|---|---|---|---|
| v4 | Flood · River level Severe | 6.0 m → 4.8 m (proposed, pending verification) | Analyst · A. Rakoto | 2026-07-18 11:20 |
| v3 | Drought · confirmation rule | 1 cycle → 2 consecutive monthly cycles | Admin | 2026-05-02 09:05 |
| v2 | Cyclone · severity cap | Cap added beyond 3 days lead | Admin | 2026-03-14 15:42 |
Append-only — no edit or delete affordance. An alert's evidence cites the threshold version it fired against, so a past decision stays reconstructable after the threshold changes. Full log on System Health.
Switch role via the header user menu's "Preview as (mockup only)" to Admin to see threshold configuration and ResponseProtocol settings.