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Trouée végétale et cadre naturel sur le cirque de Mafate - Sentier de la Roche Verre Bouteille La Possession La RéunionPhoto: Clémenceau Lauret · CC BY-SA 4.0
–Not graded
Flood & hazards in La Possession · Géorisques

The state has declared 17 natural disasters in La Possession since 1982, 11 for floods

The state lists a volcano risk here: Piton de la Fournaise. Hazard risk is not graded in France: there is no national flood map, so a town outside the mapped areas can’t be called safe from floods.

What stands out

What stands out about hazards in La Possession

From the state’s records on Géorisques. Nothing here is graded.

By hazard

5 hazards in La Possession at a glance

Bars show where the town sits among French towns of 2,500+; they are not a grade. Disaster declarations are shown, not compared.

Not on this page: wildfire maps and storm-surge levels: France publishes them only as plans.
Not graded

Why hazards aren’t graded in France

In the UK, the Hazard risk grade is the share of homes in a mapped flood zone; in the U.S., it is FEMA’s modelled yearly damage to buildings. Both rest on maps that cover the whole country. France maps flood zones in detail only in its 125 areas at highest risk (TRI), so most towns have no figure, and a blank would read as “dry”. The state’s disaster declarations don’t fill the gap: they depend on the mayor applying, and they don’t line up with the mapped zones. So La Possession has no Hazard grade, and its overall grade uses the other six subjects.

Everything on this page is shown as published. We’ll grade it when France publishes a national flood map.

Flood map

Flood zones in La Possession on the map

The state’s own layers from Géorisques, drawn over the street map. Tap a layer to switch it on or off.

© OpenStreetMap contributors · Géorisques
Medium-probability flood zone (about 1 in 100 years)Mapped area (TRI)La Possession (commune boundary)

La Possession is outside the state’s detailed flood maps, so no flood zone shows here; that doesn’t mean no flood risk (below).

Flood zones

No detailed flood map for La Possession

France maps flood zones in detail only in its areas at highest risk (TRI). La Possession isn’t one, so there is no share of residents to show. That isn’t a clean bill of health: the state has declared 11 flood disasters here since 1982, the last in January 2024.

What the state does have for La Possession: a flood risk plan (PPR), which maps the zones where building is restricted and a flood atlas (Cirque de Mafate and La Montagne) showing where past floods reached.

Check an address on Géorisques

Disaster history

17 natural disasters declared in La Possession since 1982, 11 for floods

The state’s register of natural-disaster orders, 1982 to January 2026.

  1. 2025Ground movementFebruary 26, 2025 – March 1, 2025 · order published July 16, 2025
  2. 2024Ground movementJanuary 14–16, 2024 · order published June 28, 2024
  3. 2024Wave impact on the coast · Floods and mudflowsJanuary 13–15, 2024 · order published January 23, 2024
  4. 2022Floods and mudflowsFebruary 2–4, 2022 · order published February 13, 2022
  5. 2014Floods and mudflows · Ground movementJanuary 1–3, 2014 · order published January 18, 2014
  6. 2007Floods and mudflowsFebruary 25–26, 2007 · order published March 28, 2007
Show all 11 events
  1. 2006Floods and mudflowsFebruary 18–19, 2006 · order published November 23, 2006
  2. 2002Floods and mudflows · Ground movement · Cyclonic windsJanuary 22–23, 2002 · order published February 8, 2002
  3. 1994Floods and mudflowsFebruary 10–12, 1994 · order published April 23, 1994
  4. 1993Floods and mudflowsFebruary 15–17, 1993 · order published June 27, 1993
  5. 1993Wave impact on the coast · Floods and mudflows · Ground movementJanuary 18–20, 1993 · order published June 12, 1993

Declarations by hazard · 1982–2025

Flood or mudflow9
Landslide, rockfall5
Sea and waves2
Cyclone1

Each line is a state order recognizing a natural disaster in the commune (“CatNat”), which lets insured owners claim. The latest flood began January 13, 2024; 7 flood declarations since 1995.

This count partly reflects how often a mayor applies for a declaration, so it isn’t compared between towns. It is a record of recognized claims, not a flood map. Source: GASPAR, Géorisques, file of 5 October 2026 (orders published to January 2026).

Plans and listings

The state lists 8 hazards for La Possession

Risk plans in force or in preparation, and the prefecture’s list of major risks.

Risk plans in force
1
natural and industrial
Flood atlases
2
Cirque de Mafate and La Montagne
Area at high flood risk (TRI)
No
not designated
Mayor’s risk booklet (DICRIM)
On file
published 2020
HazardRisk plan (PPR)Listed by the prefecture
River flooding and runoffApproved 2018✓
Landslides and rockfallsApproved 2018✓
Earthquake—✓
Volcano—✓
Cyclone and storm—✓
Severe weather—✓
Forest fire—✓
Dangerous goods in transit—✓

A risk plan (plan de prévention des risques, PPR) is the state’s map of where building is banned or restricted because of a hazard; it is attached to the town’s planning rules, and a seller or landlord must tell you if the home is in one. The prefecture’s file of major risks (DDRM) lists the hazards it expects in each commune.

Plans: PPR - La Possession (i+mvt)

Clay and earthquakes

Earthquake zone 2 (low)

What the ground under La Possession does: national maps, the same for every town.

Clay shrink-swell

The national clay map (BRGM 2025) covers mainland France and Corsica only; overseas départements have none.

Earthquake zones: share of French towns of 2,500+
Zone 1 · very low33%
Zone 2 · low ← La Possession36%
Zone 3 · moderate24%
Zone 4 · medium6%
Zone 5 · strong1%

La Possession is in zone 2 (low). New buildings must follow the earthquake building code (Eurocode 8) for their type. The zone sets building rules; it isn’t a forecast.

Clay: BRGM shrink-swell exposure map 2025, residents placed by INSEE’s 200 m grid. Earthquakes: national seismic zoning, decree of 22 October 2010.

Radon

Radon potential in La Possession: category 1 of 3 (low)

Radon is a natural radioactive gas from granite and volcanic rock; it builds up indoors.

Share of French towns of 2,500+ in each category
Category 1 ← La Possession66%
Category 212%
Category 322%

La Possession is in category 1, the lowest: the rocks here release little radon.

The category describes the rocks under the commune, not any home: a test is the only way to know.

Source: radon potential by commune, IRSN (now ASNR), 2019.

Industrial sites

No industrial risk plan reaches La Possession

Hazardous sites whose danger zone reaches the town, and the technological risks the prefecture lists.

Listed by the prefecture
Dangerous goods in transitroad, rail, pipeline or waterway through the town
Seveso sites
0
upper-tier Seveso sites in La Possession
0
lower-tier Seveso sites in La Possession
1
Seveso site within 5 km of the center
2.7 km
to the nearest: EDF-PEI SAS (lower tier)

Seveso sites store or use large amounts of dangerous substances; upper-tier sites have a risk plan around them. Distances are from the town’s center.

Sources: GASPAR (PPRT, DDRM), Géorisques, 5 October 2026; Seveso sites from Géorisques’ register of classified installations.

Volcano and cyclones

Volcano, cyclones and earthquakes in La Possession

The hazards that set the overseas départements apart, as the state records them; not graded.

Volcano
Piton de la Fournaise
listed by the prefecture
Cyclones
Nov–Apr
cyclone season · 1 cyclone declaration since 1982
Earthquakes
Zone 2
low seismicity · 0 earthquake declarations

In a cyclone or volcanic alert, Météo-France and the prefecture set the alert level (yellow, orange, red, then violet for a cyclone); FR-Alert sends it to every phone in the area.

Neighbors

Hazards in La Possession’s neighbors

Towns of 2,500+ within 30 km. Tap one to open its hazards page.

Le PortSaint-PaulSaint-DenisLes Trois-BassinsSalazieSainte-MarieLe PortSaint-PaulSaint-DenisLes Trois-BassinsSalazieSainte-MarieLa Possession
TownFlood zone*Seismic zoneRadon
La Possession—21
Le Port
33,969 · 4 km
—21
Saint-Paul
108,088 · 11 km
11%21
Saint-Denis
155,634 · 14 km
3.9%21
Les Trois-Bassins
7,221 · 18 km
—21
Salazie
7,268 · 20 km
—22
Sainte-Marie
37,093 · 21 km
1.3%21

* Share of residents in a mapped medium-probability flood zone; a dash means no detailed map, not no risk. Radon: category 1 to 3.

Be ready

Being ready in La Possession

Where France publishes warnings, and what to ask before you buy or rent.

Get warnings
  • Météo-France’s vigilance map gives the day’s warnings, from yellow to red (violet for a cyclone).
  • FR-Alert sends emergency alerts to every phone in the area; no sign-up needed.
Météo-France vigilance
Buying or renting
  • The seller or landlord must give you a risk statement (état des risques) for the address, listing the plans it is in.
  • They must also tell you about any natural-disaster claim paid on the home.
  • Géorisques gives the same statement for any address, free.
Check an address
Cyclone and volcano
  • Keep water, food, a radio and batteries for several days in cyclone season.
  • The volcano observatory publishes Piton de la Fournaise’s alert level.
  • The town hall’s safety plan (PCS) names the shelters.
Piton de la Fournaise volcano observatory (OVPF-IPGP)
Before you move to La Possession
  • Ask for the risk statement and read which plans the address is in.
  • Ask the town hall for its risk booklet (DICRIM) and safety plan (PCS).
  • Check that home insurance includes natural-disaster cover (it comes with fire cover).
How to read these numbers

What this data can and can’t tell you

  • Not graded. France has no national flood map, so we don’t grade hazard risk. Comparisons on this page are with other French towns of 2,500+, shown for context.
  • Mapped areas only. Flood shares exist only where the state has mapped flooding in detail (the TRI areas). A town without a figure has no map, not no risk.
  • Disaster declarations. A CatNat order recognizes a disaster so that insurers pay; it follows the commune’s application. The count partly reflects how often a mayor applies, so we show it but don’t compare towns on it.
  • Plans. A risk plan maps where building is limited; it doesn’t say any one home will flood.
  • Clay, earthquakes, radon. National maps of the ground: they describe susceptibility and set building rules, not damage or forecasts.

Check any address on Géorisques

Questions about hazards in La Possession

Does La Possession flood?

The state has declared 11 flood disasters in La Possession since 1982, the last starting January 13, 2024. The town has no detailed flood map, so check a specific address on Géorisques. A flood risk plan is in force.

Is La Possession at risk of earthquakes?

La Possession is in seismic zone 2 of 5 (low). The zone sets building rules for new construction; it isn’t a forecast.

Is there radon in La Possession?

Radon potential is category 1 of 3 (low). It describes the ground under the commune; only a test tells you a home’s level.

Are there dangerous industrial sites near La Possession?

No industrial risk plan reaches La Possession; 1 Seveso site lies within 5 km.

Is La Possession at risk from the volcano and cyclones?

The prefecture lists Piton de la Fournaise and cyclones among La Possession’s major risks. The Piton de la Fournaise volcano observatory (OVPF-IPGP) publishes the volcano’s alert level; Météo-France issues cyclone warnings.

Why doesn’t La Possession have a Hazard grade?

France maps flood zones in detail only in its areas at highest risk, so most towns would have no figure, and a blank would look like no risk. We show the data instead, and will grade it if France publishes a national flood map.

Sources: Géorisques (Ministry of Ecological Transition), GASPAR file of 5 October 2026: CatNat orders, risk plans (PPRN, PPRT, PPRM), flood atlases, DDRM, DICRIM · flood directive maps, 2020 (TRI 2nd cycle) and 2024 outlines · BRGM clay shrink-swell map 2025 · seismic zoning, decree of 22 October 2010 · ASNR (formerly IRSN) radon potential 2019 · INSEE 200 m income grid 2021 (where residents live) · map: Géorisques layers over © OpenStreetMap contributors · Seveso sites: Géorisques register of classified installations. Licence Ouverte / Open Licence (Etalab). Not graded.

Contains public sector information under the Licence Ouverte / Open Licence 2.0 (Etalab): INSEE, DGFiP, the Interior Ministry’s statistics service (SSMSI), the Ministry of Education (DEPP), the Health Ministry’s statistics service (DREES) and the Housing Ministry (Carte des loyers). Commune boundaries: IGN Admin Express.