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GCRI · Science and methods

Early warning research

A warning works only if the hazard is detected, the forecast is good enough, the message arrives in time and people know what to do. Each link can fail. The last mile, from warning to action, fails most often. The Global Centre for Risk and Innovation (GCRI) studies warning science, forecast verification and communication, in support of the authorities that alone issue warnings. Part of science and methods.

02The warning chain

Four links, each a place to fail.

  1. 01

    Risk knowledge

    Knowing which hazards threaten whom, and how badly.

  2. 02

    Detection and forecasting

    Observation and forecasts with verified skill, using forecasting and time-series analysis and Earth observation.

  3. 03

    Dissemination

    Messages that reach everyone at risk, in languages and formats they can use, including people with disabilities.

  4. 04

    Response capability

    People who understand the warning, trust it and can act on it.

03Geography

Hazards now worldwide.

Flood water, active fires and rain across the world, from NASA GIBS. Each layer carries its own date.

The interactive map needs JavaScript; the layer list and sources are below.

Layers 3

Hazards now, for this page

About this layer
Evidence
Observed (clouds leave gaps)
Source
VIIRS Global Flood Product (NASA LANCE)
Provider
NASA LANCE
Licence
NASA open data
Vintage
daily; Satellite detection; clouds leave gaps
Newest at build
2026-10-14
Resolution
about 250 m grid
Uncertainty
Satellite detection; clouds leave gaps. Satellite or model raster as the provider publishes it. Clouds, swath gaps and retrieval error leave gaps and noise; values are indicators, not measurements at a place.
Reached through
gibs.earthdata.nasa.gov, only after you allow the live map
About this layer
Evidence
Observed (clouds and overpass timing leave gaps)
Source
VIIRS NOAA-20 375 m (FIRMS) (NASA LANCE FIRMS)
Provider
NASA LANCE FIRMS
Licence
NASA open data
Vintage
daily; Satellite detection; clouds and overpass timing leave gaps
Newest at build
2026-10-13
Resolution
about 500 m grid
Uncertainty
Satellite hot-spot detections for the day shown, including gas flares and industrial heat; not a confirmed fire, an incident report or a warning.
Reached through
gibs.earthdata.nasa.gov, only after you allow the live map
About this layer
Evidence
Estimated
Source
GPM IMERG (NASA GES DISC)
Provider
NASA GES DISC
Licence
NASA open data
Vintage
daily; Satellite estimate, near real time
Newest at build
2026-10-12
Resolution
about 2 km grid
Uncertainty
Satellite estimate, near real time. Satellite or model raster as the provider publishes it. Clouds, swath gaps and retrieval error leave gaps and noise; values are indicators, not measurements at a place.
Reached through
gibs.earthdata.nasa.gov, only after you allow the live map
About this layer
Evidence
Observed
Source
VIIRS NOAA-20 corrected reflectance (NASA LANCE)
Provider
NASA LANCE
Licence
NASA open data
Vintage
daily; Satellite image
Newest at build
2026-10-14
Resolution
about 250 m grid
Uncertainty
Satellite image. Satellite or model raster as the provider publishes it. Clouds, swath gaps and retrieval error leave gaps and noise; values are indicators, not measurements at a place.
Reached through
gibs.earthdata.nasa.gov, only after you allow the live map
About this layer
Evidence
Estimated
Source
Gridded Population of the World v4.11 (NASA SEDAC (CIESIN, Columbia University))
Provider
NASA SEDAC (CIESIN, Columbia University)
Licence
CC BY 4.0
Vintage
null; Census-based estimate, static (2020)
Resolution
about 1 km grid
Uncertainty
Census-based estimate of people per square kilometre in 2020, shown as exposure context; not a count of people affected by any hazard.
Reached through
gibs.earthdata.nasa.gov, only after you allow the live map
About this layer
Evidence
Modelled (latest year GIBS publishes)
Source
MODIS Terra and Aqua land cover (MCD12Q1) (NASA LP DAAC)
Provider
NASA LP DAAC
Licence
NASA open data
Vintage
yearly; Satellite classification; latest year GIBS publishes
Newest at build
2024-01-01
Resolution
about 500 m grid
Uncertainty
Satellite land cover classes for the year shown, including croplands; a classification with known errors, not a farm register.
Reached through
gibs.earthdata.nasa.gov, only after you allow the live map

Latest available

NASA GIBS / EOSDIS · ASTER GDEM (METI, NASA) · Blue Marble (NASA) · © OpenStreetMap contributors (ODbL) · Natural Earth

Loading the latest NASA imagery.

Drag to move. Ctrl or ⌘ and scroll, pinch or the buttons to zoom; hover for the values under the pointer; reset returns to the region.

Hazards now, framed on the world.Satellite and model products as NASA publishes them, each with its own date. They are indicators, not assessments of any place.

Data: NASA GIBS · ASTER GDEM · Blue Marble · © OpenStreetMap contributors · Natural Earth · NASA EONET · U.S. Geological Survey · NASA JPL OPERA DIST-ALERTSources and licences

  • We acknowledge the use of imagery provided by services from NASA’s Global Imagery Browse Services (GIBS), part of NASA’s Earth Science Data and Information System (ESDIS). Colours redrawn from the published colour map; values averaged into hexagonal cells where shown (modified). NASA open data
  • We acknowledge the use of imagery provided by services from NASA’s Global Imagery Browse Services (GIBS), part of NASA’s Earth Science Data and Information System (ESDIS). Colours redrawn from the published colour map; values averaged into hexagonal cells where shown (modified). NASA open data
  • VIIRS near-real-time products (flood, land surface temperature, snow cover, corrected reflectance), NASA LANCE; imagery via NASA GIBS. Colours redrawn from the published colour map; values averaged into hexagonal cells where shown (modified). NASA open data
  • NASA Fire Information for Resource Management System (FIRMS), VIIRS 375 m active fire product, NASA LANCE; vector tiles via NASA GIBS. Colours redrawn from the published colour map; values averaged into hexagonal cells where shown (modified). NASA open data
  • GPM IMERG precipitation, NASA Precipitation Processing System; distributed by the NASA Goddard Earth Sciences Data and Information Services Center (GES DISC); imagery via NASA GIBS. Colours redrawn from the published colour map; values averaged into hexagonal cells where shown (modified). NASA open data
  • Center for International Earth Science Information Network (CIESIN), Columbia University. 2018. Gridded Population of the World, Version 4 (GPWv4): Population Density, Revision 11. NASA Socioeconomic Data and Applications Center (SEDAC). Licensed under CC BY 4.0. Colours redrawn from the published colour map; values averaged into hexagonal cells where shown (modified). doi:10.7927/H49C6VHW. CC BY 4.0
  • MODIS land products (vegetation indices, gross primary production, land cover), NASA LP DAAC and LANCE; imagery via NASA GIBS. Colours redrawn from the published colour map; values averaged into hexagonal cells where shown (modified). NASA open data
  • ASTER GDEM is a product of METI and NASA (ASTER Global Digital Elevation Model V003, NASA LP DAAC); imagery via NASA GIBS. Colours redrawn from the published colour map; values averaged into hexagonal cells where shown (modified). Cite as: NASA/METI/AIST/Japan Spacesystems and U.S./Japan ASTER Science Team (2019). ASTER Global Digital Elevation Model V003. doi:10.5067/ASTER/ASTGTM.003. NASA open data
  • Made with Natural Earth. Free vector and raster map data @ naturalearthdata.com. Public domain
  • © OpenStreetMap contributors (ODbL), via NASA GIBS (coastlines, boundaries, roads and place names). Colours redrawn from the published colour map; values averaged into hexagonal cells where shown (modified). ODbL
  • Blue Marble, NASA Earth Observatory; imagery via NASA GIBS. Colours redrawn from the published colour map; values averaged into hexagonal cells where shown (modified). NASA open data
  • Context on the globe and flat map: coastlines, boundaries, roads and place names from NASA GIBS reference layers (OpenStreetMap data, ODbL, © OpenStreetMap contributors); Blue Marble imagery as an optional base; 3D terrain and the elevation read-out from the ASTER GDEM elevation colour index (5 m to 200 m classes, exaggerated for legibility). Boundaries are drawn as published and imply no position on any territory.
  • Live events: NASA Earth Observatory Natural Event Tracker (EONET); events are indicative and keep their original source links.
  • Live: NASA EONET Events are indicative, not authority warnings.
  • Live: U.S. Geological Survey Events are indicative, not authority warnings.
  • Observed (EO): NASA JPL OPERA DIST-ALERT (contains modified Copernicus Sentinel data 2026). We acknowledge the use of imagery provided by services from NASA’s Global Imagery Browse Services (GIBS), part of NASA’s Earth Science Data and Information System (ESDIS).
  • NASA GIBS: We acknowledge the use of imagery provided by services from NASA’s Global Imagery Browse Services (GIBS), part of NASA’s Earth Science Data and Information System (ESDIS).
  • River discharge forecast, 30 days with range (GloFAS via Open-Meteo): Contains modified Copernicus Emergency Management Service information 2026; not a flood warning.
  • Weather data by Open-Meteo.com (https://open-meteo.com/), licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/).
  • Optional layers (20 sources in the layer list: live, forecast, observed and context) print their provider credit on the map and here when switched on; forecasts are model output and derived indices are estimates.

Layers and dates

  • Flood water, 3-day composite: VIIRS Global Flood Product, NASA LANCE · 14 Oct 2026
  • Active fires and thermal anomalies: VIIRS NOAA-20 375 m (FIRMS), NASA LANCE FIRMS · 13 Oct 2026
  • Precipitation rate, daily mean: GPM IMERG, NASA GES DISC · 12 Oct 2026
  • True colour: VIIRS NOAA-20 corrected reflectance, NASA LANCE · 13 Oct 2026
  • Population density, 2020: Population: CIESIN, Columbia University, Gridded Population of the World v4.11 (2018), NASA SEDAC, CC BY 4.0 · static
  • Land cover type (IGBP), yearly: MODIS Terra and Aqua land cover (MCD12Q1), NASA LP DAAC · 2024

04Forecast verification

The scores used to judge a forecast or a warning, and what each rewards.

ScoreWhat it measuresRange and reading
Probability of detection (hit rate)Share of observed events that were warnedZero to one; higher is better
False alarm ratioShare of warnings not followed by the eventZero to one; lower is better, and trust erodes as it rises
Brier scoreMean squared error of probability forecasts for a binary eventZero to one; lower is better; decomposes into reliability, resolution and uncertainty
Continuous ranked probability scoreError of a whole forecast distribution against the outcomeIn the units of the variable; lower is better; a proper score (Gneiting and Raftery, 2007)
Lead timeTime between warning and impactHours or days; must be long enough for the action it is meant to trigger

A score is only meaningful against a reference, such as climatology or persistence, and over enough events to be stable. Rare extremes rarely give that, which is why verification of high-impact warnings is reported with wide uncertainty.

05The global frame in 2026

Early Warnings for All, and what the monitoring shows.

The UN Secretary-General’s Early Warnings for All initiative, with its Executive Action Plan for 2023 to 2027, aims for everyone on Earth to be protected by early warning systems by the end of 2027. It is organised around the four pillars of risk knowledge, detection and forecasting, warning dissemination, and preparedness to respond, led respectively by UNDRR, WMO, ITU and IFRC. The annual Global Status of Multi-Hazard Early Warning Systems, from UNDRR and WMO, tracks progress through Sendai Framework target G. Coverage has grown. Gaps remain largest in least developed countries and small island developing states.

WMO’s guidelines on impact-based forecasting (WMO-No. 1150) mark the shift from describing the weather to describing what it will do to people and services. That needs exposure and vulnerability data the meteorological service does not hold alone.

06GCRI’s part

Research and capability for the agencies that hold the warning mandate.

GCRI studies verification, impact-based methods and last-mile communication, and supports national agencies with technical assistance through early warning capability. It issues no warnings, runs no alerting channel and never sends a simulated warning to a live audience. Verification studies are designed for the Methods and Technical series and evaluations of warning chains for the Evidence Brief series. Agencies can contribute verification archives; communities can contribute accounts of how a warning reached them, or did not.

07Research questions

What GCRI studies.

Research focuses on the links where warnings most often fail, and on evidence that agencies can use to improve their own systems.

Verification

How good are forecasts?

Measuring forecast skill, false alarms and missed events against observations.

Communication

Do messages work?

How wording, channel and trust affect whether people act.

Last mile

Who is missed?

Groups and places that warnings do not reach, and why.

08Public authority

Only authorised agencies issue warnings.

Authorised national and local agencies issue warnings. GCRI does not. In exercises, simulated warnings never reach live audiences. The Foundry system for forecast verification and warning support: NXS-EWS (multi-hazard monitoring and warning). Capability building for agencies: early warning capability.

The Consortium is not an emergency service. In immediate danger, contact your local emergency services and follow your authorities’ instructions.

11Questions

Questions and answers.

Can I receive warnings from GCRI?
No. GCRI does not issue warnings. Use the authority channels of your national meteorological, hydrological or civil protection agency.
How does GCRI work with warning agencies?
Through agreed source and methods interfaces, research collaboration and technical assistance. The agency keeps its authority and its data ownership.
What is forecast verification?
The comparison of forecasts with what was observed, to measure skill, bias, false alarms and missed events. It shows where forecasts can be trusted and where they cannot.
Why is the last mile so hard?
Because reaching everyone requires reliable channels, local languages, accessible formats, trust and the means to act. Gaps often follow existing inequalities.
Does GCRI support anticipatory action?
GCRI studies trigger evaluation and preparedness, supported by the AAP system in Foundry. Triggers never release funds or dispatch resources automatically; those decisions stay with the responsible institutions.
ReportsContribute

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Reports is the Consortium’s quarterly publication. What you know about this subject can become evidence, a case or a correction in the next edition, credited to you and published under CC BY 4.0 where it is your own work.

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The Global Centre for Risk and Innovation

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