Disaster response and humanitarian
After a cyclone, the first honest map is usually the one from orbit.
Clouds arrive with the flood. That is the problem.Flood extent mapping with optical imagery
Multispectral satellites can delineate inundated surfaces within hours of a flood peak, but only when skies clear. This page explains the spectral physics, the indices, and the honest limits of optical flood mapping.
Sentinel-2 MSI (ESA)Planet SuperDoveMODIS Terra/Aqua (NASA)
Water goes quiet. SAR hears the silence.Flood extent mapping with synthetic aperture radar
Synthetic aperture radar detects flooded land by the near-total absence of backscatter from smooth open water, day or night, through cloud. The method is fast and operationally proven, but flooded vegetation and wind chop introduce systematic errors that demand careful handling.
Sentinel-1 IW (C-band, 5.6 cm)ALOS-2 PALSAR-2 (L-band, 23.6 cm)ICEYE X-band SAR constellation
The storm passes in hours. The damage map takes days you may not have.Cyclone and tropical storm structural damage assessment
Post-cyclone structural damage assessment uses very-high-resolution optical imagery and SAR intensity change to grade buildings from destroyed to moderately damaged. Speed and cloud cover are the two variables that determine whether the map arrives in time to matter.
Maxar WorldView LegionAirbus Pléiades NeoSentinel-1 IW (SAR, C-band)
Buildings collapse silently. SAR coherence tells you where.Earthquake building-damage proxies via SAR coherence loss
Interferometric SAR coherence drops sharply where structures have collapsed or shifted, giving emergency managers a damage proxy within hours of an earthquake. The signal is real but indirect: coherence loss is not a body count or a building count, and field validation remains essential.
Sentinel-1 IW (C-band, ESA/Copernicus)ALOS-2 PALSAR-2 (L-band, JAXA)ICEYE X-band SAR constellation
The ground moved two centimetres. The radar noticed.Earthquake surface deformation measurement with InSAR
Differential InSAR turns phase shifts between two SAR passes into centimetre-scale maps of coseismic ground displacement, revealing fault geometry and slip distribution within days of a major earthquake.
Sentinel-1 IW (ESA/Copernicus)ALOS-2 PALSAR-2 (JAXA)RADARSAT Constellation Mission (CSA)
A fire pixel is 800 °C. The sensor was built for 300.Active wildfire front detection from thermal infrared
Mid-wave and thermal infrared sensors detect actively burning fire fronts by measuring radiance that saturates standard land channels, enabling near-real-time alerts. Latency, resolution floors and cloud cover set hard limits on what any system can reliably report.
VIIRS (SNPP / NOAA-20)MODIS Terra / AquaSentinel-3 SLSTR
The fire is out. The satellite record is just beginning.Post-wildfire burn scar extent and severity mapping
Burned area extent and fire severity are mapped from space using the differenced Normalised Burn Ratio, combining pre- and post-fire Sentinel-2 or Landsat imagery. Where smoke or cloud persists, SAR backscatter change from Sentinel-1 fills the gap.
Sentinel-2 MSILandsat 8/9 OLISentinel-1 IW SAR
Ash clouds are invisible to pilots. They are not invisible to physics.Volcanic ash cloud detection for aviation hazard
Volcanic ash plumes can destroy jet engines with no visible warning. Geostationary infrared sensors and hyperspectral sounders give aviation authorities the detection speed and chemical confirmation they need to close airspace before aircraft enter the cloud.
Meteosat SEVIRIGOES-16/18 ABIMetOp IASI
Magma moves silently. Radar sees the millimetres before the eruption.Volcanic edifice deformation monitoring with InSAR
Time-series InSAR turns repeated C- and L-band radar passes into surface displacement maps that reveal magma intrusion, chamber volume change, and flank creep weeks to months before a volcanic crisis becomes visible.
Sentinel-1 IW (C-band, ESA/Copernicus)ALOS-2 PALSAR-2 (L-band, JAXA)RADARSAT Constellation Mission (C-band, CSA)
The scar is visible within hours. The ground team may not arrive for weeks.Landslide mapping and post-event inventory from satellite
Fresh landslide scars have a distinct spectral signature that satellite sensors can detect within one to two days of an event. This page explains how optical change detection and SAR coherence loss combine to build event inventories that feed susceptibility models.
Sentinel-2 MSIPlanet SuperDoveAirbus Pléiades Neo
Counting shelters when no one can count peopleRefugee and IDP camp growth monitoring from space
Very-high-resolution optical satellites can detect new shelters, access tracks, and latrine pits within days of their appearance, giving UNHCR and UNOSAT population proxies where ground access is denied or unsafe.
Maxar WorldView LegionAirbus Pléiades NeoPlanet SkySat
Cities go dark. Satellites notice before the grid operators do.Power-outage and blackout mapping with nighttime lights
VIIRS Day/Night Band radiance composites detect city-block-scale electricity loss at 500 m resolution by comparing pre- and post-disaster light fields. Cloud cover, moonlight and fire glow all confound the retrieval, and honest analysis accounts for each.
VIIRS DNB (Suomi NPP)VIIRS DNB (NOAA-20)DMSP OLS (archive)
The flood hasn't arrived. The funding already has.Satellite-derived triggers for anticipatory humanitarian action
Anticipatory action frameworks release pre-positioned humanitarian funds before a disaster peaks, using objective satellite and model-derived triggers. This page explains the data inputs, trigger logic, and honest uncertainty limits that any government or humanitarian agency must understand before committing to the approach.
Sentinel-1 IW (C-band SAR)CHIRPS (Climate Hazards Group InfraRed Precipitation with Station data)GPM IMERG (Integrated Multi-satellitE Retrievals for GPM)
A disaster is declared. Fourteen space agencies start the clock.International Charter Space and Major Disasters rapid-mapping workflow
The International Charter on Space and Major Disasters routes satellite tasking and derived maps to civil protection authorities within hours of activation. This page explains the mechanics: who triggers it, what data arrives, and where the workflow breaks down.
Sentinel-1 IW (C-band SAR)Sentinel-2 MSIALOS-2 PALSAR-2 (L-band SAR)
Cloud cover hides the coast. Radar does not care.Storm surge and coastal inundation extent from SAR
When a tropical cyclone makes landfall, optical sensors go blind and the surge boundary moves by the hour. X-band SAR from ICEYE and Capella Space cuts through cloud to deliver sub-metre flood extent within hours, though mangrove and salt-marsh returns demand careful interpretation.
ICEYE X-band SAR constellationCapella Space X-band SARSentinel-1 IW (C-band, ESA)
Crops show distress weeks before people do.Vegetation stress and drought severity for food-security early warning
Satellite vegetation indices detect agricultural drought stress two to six weeks before food insecurity becomes visible on the ground. This page explains the operational methods, honest resolution limits, and the workflows used by FEWS NET and WFP VAM.
MODIS Terra/Aqua (MOD13/MYD13)VIIRS VNP13 (Suomi-NPP / NOAA-20)Sentinel-2 MSI
Knowing where water went is not the same as knowing how deep it is.Flood water depth estimation by DEM differencing
Combining SAR-derived flood extents with high-resolution elevation models lets analysts estimate water depth and inundated volume, but DEM vertical error sets a hard floor on what the method can honestly claim.
Sentinel-1 A/B (C-band SAR)Copernicus DEM GLO-30TanDEM-X (bistatic X-band InSAR)
Floodwater drains. The yield loss it leaves behind does not.Crop loss estimation from flood recession timing
Multi-temporal SAR and optical imagery can pinpoint the day floodwater leaves each agricultural parcel, then cross-reference that duration against crop submergence thresholds to estimate yield loss before harvest.
Sentinel-1 SAR (C-band, ESA)PlanetScope (Planet Labs)Sentinel-2 MSI (ESA)
Rain falls on the roof, not the land-use polygon.Urban flash flood runoff modelling from impervious surface mapping
Satellite-derived impervious surface maps at sub-10 m resolution feed directly into runoff models, replacing coarse land-use datasets that routinely underestimate sealed area in rapidly urbanising cities.
WorldView-3 (Maxar)Pleiades Neo (Airbus)Sentinel-2 MSI (ESA/Copernicus)
Aircraft drop-sondes are sparse. C-band backscatter is not.Tropical cyclone surface wind field retrieval from SAR
C-band SAR retrieves ocean surface wind speed and direction inside tropical cyclone wind fields where conventional observations are absent, using geophysical model functions to map the asymmetric structure that drives storm surge and inland damage.
Sentinel-1 A/B (C-band SAR, ESA/Copernicus)RADARSAT-2 (C-band SAR, MDA)RADARSAT Constellation Mission (C-band SAR, CSA)
The mountain moved. The satellite noticed before the road crew did.Earthquake-triggered landslide inventory from change detection
Co-seismic landslides can outnumber building collapses as a cause of earthquake fatalities, yet they are invisible to ground teams for days. Satellite change detection cuts that gap to hours, producing georeferenced inventories that guide search-and-rescue routing and infrastructure triage.
Sentinel-2 MSIPlanetScopeSPOT-7
Roads look intact from orbit until they suddenly are not.Post-earthquake road network accessibility assessment
After a major earthquake, knowing which roads are passable can determine whether aid reaches survivors within hours or days. This page explains how sub-metre optical and commercial SAR imagery, combined with road-network graph analysis, produces actionable accessibility maps.
Maxar WorldView-3Airbus Pleiades NeoICEYE SAR (X-band)
The smoke is invisible to census data. Physics is not.Wildfire smoke aerosol optical depth and population health exposure
Satellite aerosol optical depth from MODIS, VIIRS, and Sentinel-5P TROPOMI can estimate how many people are breathing hazardous air during a wildfire event, though cloud cover and coarse resolution introduce real uncertainty that any honest analysis must quantify.
MODIS Terra and AquaVIIRS Suomi-NPP and NOAA-20Sentinel-5P TROPOMI
The fire is out. The hillside is still failing.Post-wildfire erosion and debris-flow susceptibility mapping
Intense wildfire destroys the vegetation and soil structure that hold slopes together. Combining burn severity from satellite spectral indices with slope, soil type, and storm intensity data produces debris-flow susceptibility maps that can reach emergency managers before the first post-fire rain.
Sentinel-2 MSILandsat-9 OLI-2MODIS Terra/Aqua
Lava is bright. Clouds are not. Physics picks a side.Volcanic thermal anomaly detection for eruption onset warning
Shortwave and thermal infrared radiance from MODIS, VIIRS, Sentinel-2 and Landsat-9 reveal volcanic heating days to weeks before an eruption breaks the surface. MIROVA and MODVOLC translate raw radiance into alert thresholds that civil-protection agencies can act on.
MODIS Terra / AquaVIIRS Suomi-NPP / NOAA-20Sentinel-2 MSI
A volcano can go quiet on radar. Not on ultraviolet.Volcanic SO2 emission and plume dispersion tracking
Sentinel-5P TROPOMI and Aura OMI detect sulphur dioxide by its ultraviolet absorption signature, tracking plume mass and trajectory from eruption onset through dispersal. This page covers detection thresholds, ash interference, dispersion modelling, and the latency that separates a satellite overpass from an operational alert.
Sentinel-5P TROPOMIAura OMIGOES-16/17 ABI
A hillside can move for years before it kills anyone. InSAR sees it moving.Slow-moving landslide velocity mapping with InSAR time series
Persistent Scatterer and Small Baseline Subset InSAR time series detect millimetre-to-centimetre annual surface creep on slow-moving landslides, distinguishing background deformation from the episodic acceleration that often precedes catastrophic failure.
Sentinel-1 (C-band SAR, ESA/Copernicus)ALOS-2 PALSAR-2 (L-band SAR, JAXA)COSMO-SkyMed (X-band SAR, ASI)
Water stays in the reservoir. The physics of failure does not.Dam and reservoir integrity monitoring after seismic or flood events
SAR coherence loss, InSAR displacement, and optical change detection give emergency managers the first quantitative read on dam integrity within hours of an earthquake or extreme flood, before ground teams can safely approach.
Sentinel-1 SAR (C-band, ESA)ICEYE SAR (X-band, commercial)Capella Space SAR (X-band, commercial)
The wave retreats in hours. The evidence window closes in days.Tsunami inundation extent and coastal infrastructure damage mapping
Comparing pre- and post-event optical and SAR imagery reveals how far a tsunami ran inland and which coastal structures survived. The method rests on sediment deposition, vegetation removal and coherence loss, but the usable window is narrow.
WorldView-3Pleiades NeoSentinel-1 SAR (C-band, 5.6 cm)
The city's hottest blocks are predictable. Most cities do not know which ones.Urban heat island intensification and population vulnerability during heatwaves
Landsat-9 TIRS-2 and ECOSTRESS resolve intra-urban land surface temperature to 70–100 m, exposing the thermal inequality that determines who bears the greatest physiological risk during a heatwave. Knowing the gradient is the first step toward targeted intervention.
Landsat-9 TIRS-2ECOSTRESS (ISS-mounted)MODIS Terra/Aqua
Buildings stop bouncing radar. Rubble tells a different story.Conflict-related building destruction detection with SAR
SAR coherence loss and backscatter change between pre- and post-event image pairs can locate collapsed urban structures in conflict zones where no ground access exists. The method has been applied publicly in Syria, Ukraine, and Gaza by UNOSAT and academic groups.
Sentinel-1 (ESA)ICEYE SAR constellationCapella Space
Fields stop growing. Satellites notice before the harvest fails.Agricultural land abandonment and food-system disruption in conflict areas
Conflict disrupts agriculture through displacement, deliberate destruction, and fear of movement. Time-series analysis of Sentinel-2 NDVI and Sentinel-1 backscatter can detect uncultivated fields at 10 m resolution, separating war-driven abandonment from drought or voluntary fallow.
Sentinel-2 MSISentinel-1 SAR C-bandMODIS Terra/Aqua
Buildings fall in minutes. Satellites can rank the rubble before dawn.Search-and-rescue priority zone delineation after structural collapse
After an earthquake or explosion, satellite-derived damage proxies combined with building inventory and population data can rank urban blocks by probable casualty concentration, giving search-and-rescue commanders a probabilistic triage map within hours, not days.
ICEYE SAR constellationCapella Space SARPleiades Neo
The roof tells you who cannot afford to lose it.Informal settlement mapping for pre-disaster exposure assessment
Corrugated metal and tarpaulin roofs have a spectral and textural signature that formal construction lacks. Mapping that signature before a disaster, then overlaying hazard zones, turns a satellite image into a population-exposure register.
Maxar WorldView-3Airbus Pleiades NeoPlanet SkySat
Floodwater spreads what it touches. Satellites show where it touched.Flood-driven waterborne disease risk mapping
Combining SAR flood extent, land-use classification and population density, satellite analytics identify where inundation is most likely to drive waterborne disease. The output is a spatial prior for field surveillance, not a pathogen forecast.
Sentinel-1 SAR (C-band, ESA)Sentinel-2 MSI (ESA)PlanetScope (Planet Labs)
Floodwaters retreat in days. The sediment they leave reshapes land for years.Post-flood sediment and debris deposition mapping
Spectral turbidity indices and DEM differencing reveal where floods deposited sediment and debris, quantifying volume changes that field surveys rarely capture at scale. Cloud cover and vertical accuracy set hard limits on what satellites can honestly deliver.
Sentinel-2 MSILandsat 8/9 OLIPlanet SuperDove
The lake expands for months before it kills in hours.Glacial lake outburst flood hazard monitoring
Glacial lake outburst floods give little warning at ground level but leave a long satellite record of precursor signals. Multi-sensor monitoring of lake area, dam deformation and ice velocity can push that warning window from minutes to weeks.
Sentinel-2 MSISentinel-1 SAR (C-band)Landsat 8/9 OLI
Tarpaulins and tin roofs look identical from 500 metres. Not from 30.Emergency shelter material and density classification after displacement
Sub-metre multispectral and panchromatic imagery, combined with texture analysis and supervised classification, can distinguish tarpaulin, canvas, and corrugated-metal shelter types within newly established displacement camps to inform logistics and protection planning.
Maxar WorldView-3Airbus Pléiades NeoPlanet SkySat
Cloud hides the disaster. It cannot hide what floats on the water.Disaster-triggered oil spill and chemical release detection from SAR
Earthquakes, floods, and industrial accidents release hydrocarbons into waterways before optical sensors can see through cloud cover. SAR detects surface oil films through Bragg-scattering suppression, producing dark signatures in C- and X-band imagery within hours of an event.
Sentinel-1 A/B (C-band SAR)ICEYE SAR constellation (X-band)Capella Space (X-band SAR)
A substation sitting 30 cm above the flood line needs 10 cm accuracy, not 2 m.Critical infrastructure flood exposure from LiDAR-fused elevation models
Coarse global DEMs misplace flood risk for hospitals, substations and water-treatment plants by metres. Fusing airborne LiDAR bare-earth models with SAR-derived flood extents narrows that uncertainty to operationally useful bounds.
Airborne LiDAR (national survey datasets)Sentinel-1 SAR (C-band, ESA)ICEYE SAR (X-band commercial)
Leaves stay green. Snapped trunks still show up in the radar.Post-cyclone mangrove canopy loss and coastal protection deficit mapping
Cyclone damage to mangroves is routinely invisible to optical sensors for weeks. L-band SAR and Sentinel-2 red-edge indices together reveal structural loss and the coastal flood exposure that follows.
ALOS-2 PALSAR-2Sentinel-1 C-band SARSentinel-2 MSI
The fire is moving. The question is whether the road is already inside it.Wildfire perimeter dynamics and evacuation route accessibility
Near-real-time perimeter extraction from VIIRS, Sentinel-3 SLSTR and GOES-16/17 ABI, overlaid on road networks, tells emergency managers which evacuation corridors are already compromised and which will be within the hour.
VIIRS (Suomi-NPP / NOAA-20)GOES-16 / GOES-17 ABISentinel-3 SLSTR
Extent tells you where. Duration tells you what it costs.Flood insurance loss estimation using SAR-derived inundation duration
Flood damage scales with how long water sits on a property, not just how far it spreads. Multi-date Sentinel-1 SAR time series can reconstruct inundation recession curves at parcel level, giving insurers and reinsurers an independent, physics-based input to actuarial loss models.
Sentinel-1 A/B SAR (C-band, 5.405 GHz)ICEYE SAR constellation (X-band)Capella Space SAR (X-band)
The cloud arrives with the eruption. SAR does not wait for clear skies.Volcanic lahar flow path and deposit mapping from SAR and optical
Lahars can bury roads, bridges and settlements within hours of an eruption, often under thick volcanic cloud. Sentinel-1 SAR amplitude change detection maps deposit extent regardless of weather; Sentinel-2 optical composites refine boundaries once skies clear.
Sentinel-1 SAR (C-band, ESA)Sentinel-2 MSI (ESA)TanDEM-X (DLR)
The grid comes back unevenly. Satellites record exactly where it hasn't.Nighttime light recovery tracking as a reconstruction progress proxy
Nighttime light radiance from VIIRS Day-Night Band composites gives disaster responders and donors an objective, neighbourhood-scale measure of power restoration after earthquakes, hurricanes, and conflict. The method is fast, free, and honest about what it cannot see.
VIIRS Day-Night Band (Suomi-NPP / NOAA-20)DMSP-OLS archiveLuojia-1A