---
title: "GloFAS 210-day ensemble discharge (50 members)"
method: GET
path: "/api/v1/weather/flood/ensemble"
tags: ["Environment"]
---

# GloFAS 210-day ensemble discharge (50 members)

`GET /api/v1/weather/flood/ensemble`

210-day seasonal-outlook ensemble river discharge from GloFAS v4 served via Open-Meteo. Each row carries all 50 ensemble members plus percentile bands (p0, p25, p50, p75, p100) and the ensemble mean. Useful for hydrology, insurance, and supply-chain risk analysis. Data by Open-Meteo.com, CC BY 4.0.

## Query parameters

- `latitude` number, nullable — Latitude in decimal degrees (-90 to 90). Provide latitude+longitude OR river.
- `longitude` number, nullable — Longitude in decimal degrees (-180 to 180). Provide latitude+longitude OR river.
- `river` string, nullable — River name as an alternative to latitude+longitude. Curated rivers resolve to a validated GloFAS-mainstem cell; others fall back to the geocoder.
- `forecast_days` integer — Forecast horizon in days (1-210).
- `past_days` integer — Historical lookback in days (0-92).
- `cell_selection` string, nullable — Grid-cell selection strategy: nearest (default), land, or sea.

## Response `200`

Daily rows with 50 ensemble members plus summary bands.

- EnvelopeFloodEnsembleData
  - `data` FloodEnsembleData, required — GloFAS v4 210-day seasonal ensemble with 50 members and percentile bands.
    - `latitude` number, required — Snapped grid-cell latitude.
    - `longitude` number, required — Snapped grid-cell longitude.
    - `elevation_m` number, nullable — Grid-cell elevation above sea level (m).
    - `timezone` string, nullable — Timezone of the `date` field.
    - `units` object, required — Unit mapping for every band variable.
    - `mode` string, required — Always `ensemble` for this endpoint.
    - `forecast_days` integer, required — Number of forecast days (1-210).
    - `past_days` integer, required — Number of past days included (0-92).
    - `data` FloodEnsembleRow[], required — Row-oriented list of daily discharge rows, each with 50 ensemble members.
      - `date` string, required — Observation date in ISO 8601 UTC.
      - `river_discharge` number, nullable — Deterministic discharge from the summary bands (m3/s).
      - `river_discharge_mean` number, nullable — Ensemble mean discharge (m3/s).
      - `river_discharge_median` number, nullable — Ensemble median p50 (m3/s).
      - `river_discharge_max` number, nullable — Ensemble max p100 (m3/s).
      - `river_discharge_min` number, nullable — Ensemble min p0 (m3/s).
      - `river_discharge_p25` number, nullable — Ensemble p25 lower band (m3/s).
      - `river_discharge_p75` number, nullable — Ensemble p75 upper band (m3/s).
      - `ensemble_members` number[], required — 50 parallel ensemble member values (m3/s), index 0 = member 01.
  - `meta` SugraMeta, required — Metadata attached to every /api/v1/* response envelope.
    - `endpoint` string, required — Requested endpoint path.
    - `data_time` string, required — ISO 8601 UTC timestamp of the source data, not of the request.
    - `response_time` string, required — ISO 8601 UTC timestamp when this response was produced.
    - `provider` string, required — API name and version.
    - `source` string, nullable — Identifier of the primary upstream source used for this response.
    - `attribution` string, nullable — Human-readable attribution mandated by an upstream source (e.g. a securities regulator or self-regulatory organization). Present only on responses whose source requires the owner and source to be clearly identified. Do not remove or alter it when using the response.
    - `fallback_used` boolean, nullable — True when the primary source failed and a fallback produced the data.
    - `fallback_chain` string[], nullable — Ordered list of sources attempted, in the order they were tried.
    - `cached` boolean, nullable — True when this response was served from the internal cache.
    - `stale` boolean, nullable — True when the cached response was returned after the upstream rate-limited or errored. Clients can use this to detect degraded data.

## Other responses

- `401` — Missing or invalid `x-api-key` header. JSON body with a stable `code` distinguishing `missing_api_key` (no header sent) from `invalid_api_key` (header sent, key not accepted); any other 401 source carries the generic `unauthorized` with its detail as `reason`. Plus `hint`. `plan` is always null on 401 - an unauthenticated request has no plan; quota exhaustion is 429, not 401.
- `422` — Validation Error
- `429` — Daily rate limit exceeded. Check `X-RateLimit-Reset` for the next window.
- `503` — Upstream source is temporarily unavailable. Retry after a short delay.

---

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