Mayotte Climate, Multi-Hazard And Disaster Risk Profile
Mayotte is a highly exposed small island territory in the Mozambique Channel. Its disaster risk is shaped by tropical cyclones, coastal flooding, heavy rainfall, landslides, drought and water scarcity, coastal erosion, sea-level rise, and a major seismo-volcanic crisis that began offshore in 2018. Climate change is expected to intensify heat, rainfall extremes, coastal stress, and the destructive potential of severe tropical cyclones. Météo-France has started releasing fine-scale climate projections for French overseas territories, including Mayotte, to support adaptation planning Météo-France.
| Hazard | Risk and Vulnerability Context |
|---|---|
| Tropical cyclones and strong winds | Mayotte is exposed to severe Southwest Indian Ocean cyclones. Cyclone Chido in December 2024 caused catastrophic damage, with regional IFRC reporting identifying Mayotte among the worst affected areas IFRC. |
| Heavy rainfall and flooding | Intense rainfall can trigger flash floods, river overflow, urban flooding, and marine submersion. Mayotte has a formal flood risk management process under the French/European Flood Directive and PGRI framework Mayotte State Services. |
| Coastal erosion and sea-level rise | Low-lying coastal settlements, roads, ports, beaches, mangroves, coral reef ecosystems, and public infrastructure are vulnerable to shoreline retreat, storm surge, marine flooding, and saltwater intrusion. |
| Drought and water scarcity | Mayotte’s water supply depends heavily on rainfall. During the 2023 water crisis, the Government described an exceptional drought, major water cuts, and daily bottled-water distribution to the population Government of France. |
| Landslides and slope instability | Steep volcanic terrain, informal hillside settlements, deforestation, poor drainage, and intense rainfall increase landslide and erosion risks. |
| Earthquake and volcanic risk | Since May 2018, Mayotte has experienced thousands of small and medium earthquakes, and a major underwater volcanic edifice was discovered about 50 km offshore. REVOSIMA monitors this seismic-volcanic activity BRGM. |
| Public health risks | Flooding, cyclone damage, water shortages, overcrowding, and poor WASH conditions increase risks of waterborne disease, heat stress, vector-borne disease, and post-disaster health service disruption. |
Underlying Vulnerability
Mayotte’s risk is amplified by very high social vulnerability. INSEE estimates the population at about 329,000 in 2025; 77% of residents live below the national poverty line, and unemployment reached 29% in 2024 INSEE. Many people live in informal or fragile housing, including settlements exposed to wind, flooding, slope instability, and poor water and sanitation access. This means the same cyclone, flood, drought, or earthquake can produce much higher human impacts than in better-serviced territories.
Most Vulnerable Sectors
Housing and informal settlements
Water supply, sanitation, and hygiene systems
Health services and emergency care
Roads, port, airport, electricity, and telecommunications
Schools and public buildings used as shelters
Fisheries, small agriculture, and food systems
Coastal ecosystems, mangroves, reefs, beaches, and lagoons
Migrant, undocumented, poor, women-headed, child-headed, elderly, and disabled households
Priority Risk Reduction Needs
Mayotte needs a multi-hazard, climate-informed risk management approach focused on resilient housing, cyclone shelters, flood and landslide zoning, coastal protection, water-security infrastructure, inclusive early warning, and risk-sensitive reconstruction after Chido. A strong CRVA should combine cyclone wind maps, flood and storm-surge maps, drought and water-supply stress analysis, seismic-volcanic monitoring, social vulnerability mapping, and critical infrastructure exposure assessment.
Mayotte: Climate, Multi-Hazard And Disaster Risk And Vulnerability
Mayotte is a small, densely populated French overseas department in the southwest Indian Ocean. Its disaster risk is shaped by a tropical maritime climate, steep volcanic terrain, high coastal settlement, fragile water infrastructure, rapid population pressure, and a large share of vulnerable housing. The territory faces both hydro-meteorological and geophysical hazards.
Climate Context
Mayotte has a hot, humid, tropical maritime climate with relatively small annual temperature variation and average annual rainfall above 1,500 mm. The climate is influenced by the northwest monsoon during the hot wet season and the southeast trade winds during the cooler dry season. The year is broadly divided into a hot rainy season and a cooler dry season, with short transition periods between them Météo-France Mayotte.
Climate change is already affecting Mayotte through rising temperatures, changing rainfall patterns, stronger heat stress, drought pressure, and increased exposure to extreme weather events. Météo-France notes that Mayotte’s small size and marked relief require localized climate analysis to understand future climate risks Météo-France Mayotte climate change.
Major Hazards And Risk Drivers
| Hazard | Main Risk Characteristics | Vulnerability Implications |
|---|---|---|
| Tropical cyclones and storms | Strong winds, intense rainfall, storm surge, wave action, coastal damage | Severe damage to weak housing, power, communications, ports, roads, schools, health facilities |
| Flooding | River overflow, urban runoff, coastal flooding, marine submersion | High exposure of coastal settlements, informal housing, drainage congestion, damage to assets and services |
| Drought and water scarcity | Rainfall deficits, low reservoir levels, water rationing | Major WASH, health, livelihood, school, business, and social stability impacts |
| Landslides and erosion | Steep slopes, deforestation, intense rainfall, unstable soils | Damage to settlements, roads, agricultural land, and lagoon ecosystems through sedimentation |
| Coastal erosion and sea-level rise | Shoreline retreat, storm surge, saline intrusion, wave impacts | Threats to coastal communities, tourism assets, roads, water resources, mangroves, reefs, and beaches |
| Earthquakes and volcanic activity | Moderate seismic risk and ongoing seismo-volcanic monitoring since the 2018 crisis | Structural risk to weak buildings, possible landslides, tsunami-related concerns |
| Tsunami and marine hazards | Possible earthquake- or landslide-triggered tsunami and coastal inundation | High concern because much of the population and infrastructure are concentrated along the coast |
| Public health emergencies after disasters | Water contamination, overcrowding, damaged sanitation and health services | Increased risk of waterborne disease, especially after cyclones, floods, and water shortages |
Mayotte is officially recognized as highly exposed to flood risk, including river flooding, urban runoff, marine submersion during storms or cyclones, and tsunami risk. Government flood-risk planning notes that around 56,000 people live in flood-hazard areas, including many in precarious housing Mayotte Prefecture flood-risk planning.
Key Vulnerability Factors
Coastal concentration of people and assets
A large share of settlements, public infrastructure, roads, ports, markets, and economic activity is located near the coast. This increases exposure to storm surge, coastal flooding, sea-level rise, erosion, and tsunami risk.Precarious housing and informal settlements
INSEE reported in 2026 that, before Cyclone Chido, around four in ten dwellings in Mayotte were still made of sheet metal, and 25% of households lacked running water in their home. Among households living in sheet-metal houses, 61% lacked running water INSEE Mayotte housing analysis.Water insecurity
Mayotte’s water supply depends heavily on rainfall. During the 2023 water crisis, the French government extended bottled-water distribution to the whole population because of exceptional drought and major water cuts French Government water crisis update. This makes drought a systemic risk, not only an agricultural hazard.Fragile infrastructure and services
Water supply, roads, drainage, electricity, telecommunications, schools, and health services are highly vulnerable to cyclone, flood, and landslide impacts. Cyclone Chido demonstrated how pre-existing poverty, overcrowding, inadequate infrastructure, and limited resources can amplify disaster losses Reuters.Geophysical and coastal risk complexity
BRGM supports Mayotte on natural hazard mapping, groundwater, coastal risks, erosion, seismic hazards, and the seismo-volcanic monitoring network. It also notes that population growth is increasing pressure on coastal areas, where erosion and coastal flooding threaten communities and infrastructure BRGM Mayotte.
Most Exposed Sectors
Housing and settlements: informal and sheet-metal housing, coastal settlements, steep-slope neighborhoods.
Water and sanitation: reservoirs, pipes, household water access, emergency water distribution systems.
Health: hospitals, clinics, disease surveillance, WASH-related disease control.
Transport and logistics: roads, ports, airport access, bridges, coastal routes.
Education: school closures during cyclones, floods, water shortages, and heat stress.
Agriculture and food security: drought, rainfall variability, erosion, crop damage, market disruption.
Ecosystems: mangroves, coral reefs, lagoon, beaches, forests, and watersheds.
Tourism and local economy: beach erosion, cyclone damage, water scarcity, degraded ecosystems.
Priority Risk Reduction And Early Warning Actions
Strengthen multi-hazard early warning for cyclones, heavy rainfall, floods, landslides, storm surge, tsunami, drought, heat, and water stress.
Improve last-mile warning dissemination in multiple languages and formats, especially for informal settlements and migrant communities.
Upgrade hydrometeorological monitoring: rainfall stations, river gauges, coastal/tide gauges, landslide-prone slope monitoring, drought and reservoir monitoring.
Develop impact-based forecasting linked to evacuation, shelter, school closure, health preparedness, water distribution, and road/port operations.
Expand resilient housing, cyclone-safe shelters, and risk-informed land-use planning.
Protect and restore watersheds, mangroves, reefs, and drainage corridors to reduce erosion, flooding, and coastal risk.
Strengthen emergency water security, including storage, leakage reduction, desalination backup, groundwater protection, and drought contingency planning.
Integrate climate risk, flood-risk maps, coastal-risk maps, and social vulnerability data into local development planning.
In summary, Mayotte’s disaster risk is not caused by hazards alone. It is the interaction of cyclones, floods, drought, coastal hazards, seismic-volcanic risk, fragile infrastructure, precarious housing, water insecurity, and social vulnerability that creates high disaster risk.
Underlying Vulnerability
Mayotte’s risk is amplified by very high social vulnerability. INSEE estimates the population at about 329,000 in 2025; 77% of residents live below the national poverty line, and unemployment reached 29% in 2024 INSEE. Many people live in informal or fragile housing, including settlements exposed to wind, flooding, slope instability, and poor water and sanitation access. This means the same cyclone, flood, drought, or earthquake can produce much higher human impacts than in better-serviced territories.
Most Vulnerable Sectors
- Housing and informal settlements
- Water supply, sanitation, and hygiene systems
- Health services and emergency care
- Roads, port, airport, electricity, and telecommunications
- Schools and public buildings used as shelters
- Fisheries, small agriculture, and food systems
- Coastal ecosystems, mangroves, reefs, beaches, and lagoons
- Migrant, undocumented, poor, women-headed, child-headed, elderly, and disabled households
Priority Risk Reduction Needs
Mayotte needs a multi-hazard, climate-informed risk management approach focused on resilient housing, cyclone shelters, flood and landslide zoning, coastal protection, water-security infrastructure, inclusive early warning, and risk-sensitive reconstruction after Chido. A strong CRVA should combine cyclone wind maps, flood and storm-surge maps, drought and water-supply stress analysis, seismic-volcanic monitoring, social vulnerability mapping, and critical infrastructure exposure assessment.