Photo: Pymouss · CC BY-SA 4.0Léry is on Canada’s flood inventory: 1 listed, led by Gouvernement du Québec
Wildfire is rare near Léry: 0% of the land within 25 km has burned since 1986, a burn rate of 0.001% a year. Earthquakes add more: NRCan’s model puts building losses at $0.16 a year per $1,000 of value, against $0.030 for the typical town. Léry’s survey area, 8.2% over the radon guideline, is close to the typical town’s 6.6%. Hazard risk gives Léry a grade of C, from earthquakes and radon alone.
What stands out about Léry’s hazards
For Léry, from NRCan’s seismic model, Health Canada’s radon survey, the national burned-area record and the flood map inventory.
What Léry faces
Each hazard against its own yardstick; meters run from low to high on that yardstick.
Wildfire
Earthquakes
Radon
Flood study
Léry grades C for hazard risk
Risk averages earthquakes and radon; wildfire joins only where it pulls the average down, so a town like Léry with little fire nearby would get no credit for it.
Its place: #283 of 507 in Quebec and #2,239 of 2,589 Canadian towns.
How sure: Earthquake losses are a model’s expectation over many years, not a forecast for any one. The burned-area record misses fires under about 10 ha and most grass and farm fires.
Few fires near Léry: 0.2% within 5 km, 0% within 25 km
Past fire around Léry’s homes, from the national burned-area record, with the fuel within 5 km.
Léry burns at 0.001% a year, low against 0.000% for the typical Canadian town.
Forest makes up 1.5% of the land within 5 km of Léry and 1.8% within 25 km, little for a forest fire to run through.
Shares of land within 5 and 25 km of populated blocks: burned at least once in 1986–2025 (CWFIS burned-area composite), forest fuel and grass (fire behaviour fuel types, 2026, 250 m grid).
Burn rate a year, towns in Quebec · highest of 513
In the upper half in Quebec but far from Mistissini (0.31%): Léry ranks 136th of 513, at 0.001% a year.
Each bar: the yearly average share of land within 25 km of a town’s homes that burned, 1986–2025 (CWFIS); the seven highest towns of 2,500 people or more.
Beside 2,610 Canadian towns, Léry reads low, with 92% of them; only 7.5% rank higher.
Bands of the yearly burn rate: low under 0.05%, moderate under 0.25%, high under 1%, very high 1% or more; towns of 2,500 people or more.
Fire danger and active fires (CWFIS)
Canadian Wildland Fire Information System: National Burned Area Composite 1986–2025 and fire behaviour fuel types (2026), Natural Resources Canada. Measured within 25 km and 5 km of each populated dissemination area; past fire, not a forecast.
Gouvernement du Québec has mapped flooding for Léry (1 study)
What Canada’s Flood Map Inventory lists for Léry: who studied flooding and where to see their maps.
The flood study touching Léry is Gouvernement du Québec’s, dated 1977; its own map shows the zones street by street.
| Study | By | Year | Status |
|---|---|---|---|
| St-Louis-Varennes | Gouvernement du Québec | 1977 | final |
Towns with a flood study on file
Only 45% of towns in Quebec have a flood study, short of Canada’s 58%; Léry is one of them.
NRCan Canada Flood Map Inventory: a study footprint touching the town’s boundary; towns of 2,500 people or more.
The grade leaves flood out, since a study area says nothing about how many of Léry’s homes are at risk.
The inventory’s own caution (NRCan): “The Canada Flood Map (CFM) does not include every flood hazard map in Canada and may be incomplete or contain inaccuracies. It should not be relied upon as the official source of flood mapping information. Furthermore, if a map appears to be missing, this does not necessarily mean that the area has never been mapped. For the official version of a map, updated information, or confirmation of applicable regulations, please contact the local authority responsible for flood mapping.”
Natural Resources Canada, Canada Flood Map Inventory; links go to each study’s owner.
Shaking is Léry’s costliest hazard: $0.16 a year per $1,000
Expected yearly building losses from earthquakes, from Natural Resources Canada’s model.
At $0.16 per $1,000, Léry carries roughly 5.3 times the typical Canadian town’s earthquake risk ($0.030).
Shaking damage a year per $1,000 of building value
The median in Quebec is $0.14; Léry, at $0.16, is right beside it, and La Pocatière tops the list at $0.48.
NRCan seismic risk model (2022): mean yearly building loss per $1,000 of value; medians of towns of 2,500 people or more.
In the upper part of Canada’s range: 15% of its 2,611 towns expect more damage than Léry.
Each column: the share of Canada’s towns of 2,500 people or more in that range of yearly loss per $1,000 (NRCan, 2022).
For Léry the model prices shaking damage to buildings, nothing more.
Natural Resources Canada, Canada’s Seismic Risk Model (2022), by census subdivision (2016 boundaries; a few 2021 subdivisions take their residents’ mean).
8.2% of homes tested around Léry are over the radon guideline
Long-term radon tests in homes across the survey area, against Health Canada’s guideline.
8.2% of tested homes around Léry were over the guideline, much like the typical Canadian town at 6.6%.
Tested homes over 200 Bq/m³
Over 600 Bq/m³
Around Léry, 8.2% of tests topped the guideline, about the same as the typical town in Quebec (8.2%).
Health Canada radon survey (2009–2011), by 2007 health region; medians of towns of 2,500 people or more.
26% of Canada’s 2,611 towns have more homes over 200 Bq/m³ than Léry’s 5–10% band, which holds 37%.
Each bar: the share of Canada’s towns of 2,500 people or more whose survey area had that share of tests over 200 Bq/m³.
Neighbouring homes in Léry can differ a lot; only a long-term test tells you about yours.
Health Canada, Cross-Canada Survey of Radon Concentrations in Homes (2009–2011). · Data for radon tests covers the Monteregie health region
Where to get warnings in Léry
Environment and Climate Change Canada issues the weather alerts for Léry; Alert Ready carries the urgent ones to phones, radio and TV.
| Alert | What it means |
|---|---|
| Warning | Severe weather is happening or about to: act now. |
| Watch | Conditions favour severe weather: be ready. |
| Advisory | Weather that is less severe but could disrupt the day. |
| Special weather statement | Unusual weather worth knowing about. |
| Special air quality statement | Poor air, often wildfire smoke. |
In fire season, check CWFIS for danger and active fires around Léry, and listen to local authorities for orders.
Weather alerts (ECCC) · Alert Ready · Fire danger and active fires (CWFIS)
Hazards in the places around Léry
Wildfire band, earthquake risk, radon and flood studies for each place nearby.
| Town | Wildfire | Quake $/1,000 | Radon | Flood study |
|---|---|---|---|---|
| Léry | Low | $0.16 | 8.2% | Yes |
| Châteauguay 53,508 · 5.6 km | Low | $0.20 | 8.2% | Yes |
| Mercier 16,036 · 6.2 km | Low | $0.19 | 8.2% | Yes |
| Beauharnois 15,285 · 7.5 km | Low | $0.18 | 8.2% | Yes |
| Notre-Dame-de-l'Île-Perrot 11,716 · 9.6 km | Low | $0.14 | 8.2% | Yes |
| Kahnawake 11,142 · 10.0 km | Low | – | 8.2% | Yes |
| Sainte-Martine 5,884 · 10 km | Low | $0.19 | 8.2% | Yes |
The fire record around Beauharnois is a touch heavier than Léry’s, but the band is the same: low (here low).
Radon is the survey area’s figure, so neighbours in one area share it.
Get ready for what Léry faces
What to do about the hazards Léry faces, and what to ask before you buy.
- Test for three months in winter.
- Over 200 Bq/m³: fix it.
- Kits are cheap; pros test too.
- Never drive through floodwater.
- Move papers and medicines upstairs.
- Ask whether your street is mapped.
- Drop, cover and hold on.
- Strap the water heater down.
- Keep 72 hours of supplies.
- Has it had a radon test?
- Check the address on the flood map.
- Are flood and wildfire insured?
- Is earthquake cover included?
What this data can and can’t tell you
- Wildfire counts one way. Burned land within 25 km of where people live, averaged over 1986–2025 and checked for fuel near homes, is the measure; it looks back, not ahead, and only ever counts against Léry.
- Flood studies aren’t flood zones. NRCan’s inventory says where flood mapping exists, not where water goes; the map’s owner is the authority for Léry.
- Earthquakes are modelled. The earthquake figure is an expected loss, not a forecast, worked out by NRCan for each census subdivision, Léry’s included.
- Radon is a survey. About 14,000 homes were tested across Canada in 2009–2011, and the share over the guideline for Léry is its health region’s, the survey’s design unit.
Questions about flooding and hazards in Léry
Is radon a problem in Léry?
In Health Canada’s survey, 8.2% of 110 homes tested in Léry’s area were above 200 Bq/m³, though only a test tells you about one house.
Does Léry flood?
There is flood mapping for Léry on the national inventory, each study linked to its owner’s map, none of them graded.
Is Léry at risk of wildfire?
Less than most of Canada: 0% of the land within 25 km of Léry has burned since 1986, the last in 2025, a low band that leaves Risk alone.
How big is the earthquake risk in Léry?
NRCan’s model expects shaking to cost buildings in Léry $0.16 a year for every $1,000 of their value, on average over many years.
How is Léry’s Hazard risk Grade worked out?
Hazard risk gives Léry C, weighing earthquakes and radon and counting wildfire only against it.
Seismic risk: Natural Resources Canada. Radon: Health Canada. Wildfire: Canadian Wildland Fire Information System. Flood studies: Natural Resources Canada, Canada Flood Map Inventory. Contains information licensed under the Open Government Licence – Canada.
Sources: NRCan, Canada’s Seismic Risk Model 2022 · Health Canada, Cross-Canada Survey of Radon Concentrations in Homes · CWFIS, National Burned Area Composite and FBP fuel types · NRCan, Canada Flood Map Inventory. Under the Statistics Canada Open Licence.
Adapted from Statistics Canada (Census of Population 2021, population estimates 2025, 2021 census boundaries) under the Statistics Canada Open Licence; this does not constitute an endorsement by Statistics Canada. Neighbourhood names in some cities © OpenStreetMap contributors (ODbL).