Photo: P199 · CC BY-SA 4.0Les Coteaux’s hazards at a glance: a low wildfire record and 8.2% of area homes over the radon guideline
The burned-area map is nearly blank around Les Coteaux, 0% within 25 km since 1986, 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. Hazard risk gives Les Coteaux a grade of C, from earthquakes and radon alone.
What stands out about Les Coteaux’s hazards
For Les Coteaux, from NRCan’s seismic model, Health Canada’s radon survey, the national burned-area record and the flood map inventory.
What Les Coteaux faces
Each hazard against its own yardstick; meters run from low to high on that yardstick.
Wildfire
Earthquakes
Radon
Flood study
Les Coteaux grades C for hazard risk
For Les Coteaux, Risk will be the average of earthquakes and radon, with wildfire added only if it makes the average worse.
Its place: #277 of 507 in Quebec and #2,230 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 Les Coteaux: 0% within 5 km, 0% within 25 km
Past fire around Les Coteaux’s homes, from the national burned-area record, with the fuel within 5 km.
Low: the land around Les Coteaux burns at 0.001% a year, where the typical Canadian town sees 0.000%.
No fire has burned within 5 km of Les Coteaux’s homes since 1986; the nearest burn is 5.6 km away.
With 0.3% forest fuel within 5 km and 3% within 25 km, the land around Les Coteaux gives a fire little to burn.
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
At 0.001% a year, Les Coteaux ranks 136th of the 513 towns in Quebec; Mistissini leads at 0.31%.
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.
7.5% of Canada’s 2,610 towns burn fast enough to rank moderate or above; Les Coteaux stays low, with 92%.
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.
No flood study is listed for Les Coteaux
What Canada’s Flood Map Inventory lists for Les Coteaux: who studied flooding and where to see their maps.
Nationally, Les Coteaux has no listed flood study; the municipality is the place to ask.
Towns with a flood study on file
Les Coteaux has no flood study on file; only 45% of towns in Quebec do, against 58% across Canada.
NRCan Canada Flood Map Inventory: a study footprint touching the town’s boundary; towns of 2,500 people or more.
Flood mapping is shown for Les Coteaux to be opened and checked, never turned into a grade.
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.”
Earthquakes cost buildings in Les Coteaux $0.16 per $1,000 a year
Expected yearly building losses from earthquakes, from Natural Resources Canada’s model.
Roughly 5.2 times the typical $0.030: Les Coteaux’s $0.16 marks real seismic exposure.
Shaking damage a year per $1,000 of building value
Les Coteaux’s $0.16 is close to the median in Quebec, $0.14; La Pocatière is highest 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.
Les Coteaux sits above most of Canada’s 2,611 towns on earthquake risk; 15% are higher.
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).
Only shaking damage to buildings in Les Coteaux is counted; landslides, liquefaction, tsunami and fire after a quake aren’t.
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 Les Coteaux are over the radon guideline
Long-term radon tests in homes across the survey area, against Health Canada’s guideline. · Shared with the rest of the Monteregie health region: radon tests
Les Coteaux’s area, at 8.2%, is close to the 6.6% of the typical Canadian town.
Tested homes over 200 Bq/m³
Over 600 Bq/m³
Les Coteaux’s area, at 8.2%, is close to the median in Quebec (8.2%).
Health Canada radon survey (2009–2011), by 2007 health region; medians of towns of 2,500 people or more.
Radon tops the guideline in a modest share of homes around Les Coteaux, a band holding 37% of Canada’s 2,611 towns; 26% rank above.
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.
Health Canada advises testing every home, Les Coteaux’s included, whatever the area’s figure.
Health Canada, Cross-Canada Survey of Radon Concentrations in Homes (2009–2011).
Where to get warnings in Les Coteaux
Alerts for Les Coteaux come from Environment and Climate Change Canada and, for emergencies, Alert Ready.
| 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. |
Fire danger and active fires near Les Coteaux are mapped daily by the Canadian Wildland Fire Information System; evacuation orders come from the municipality or province.
Weather alerts (ECCC) · Alert Ready · Fire danger and active fires (CWFIS)
How Les Coteaux’s neighbours compare on hazards
Wildfire band, earthquake risk, radon and flood studies for each place nearby.
| Town | Wildfire | Quake $/1,000 | Radon | Flood study |
|---|---|---|---|---|
| Les Coteaux | Low | $0.16 | 8.2% | None listed |
| Coteau-du-Lac 7,839 · 4.6 km | Low | $0.14 | 8.2% | None listed |
| Saint-Zotique 10,445 · 4.7 km | Low | $0.11 | 8.2% | None listed |
| Salaberry-de-Valleyfield 47,002 · 7.2 km | Low | $0.19 | 8.2% | None listed |
| Saint-Polycarpe 2,549 · 9.1 km | Low | $0.18 | 8.2% | None listed |
| Saint-Clet 1,784 · 9.5 km | Low | $0.18 | 8.2% | None listed |
| Sainte-Barbe 1,993 · 10 km | Low | $0.17 | 8.2% | None listed |
Sainte-Barbe burns a little more than Les Coteaux, in the same low band (low here).
Radon is the survey area’s figure, so neighbours in one area share it.
Get ready for what Les Coteaux faces
Practical steps for Les Coteaux’s hazards, most pressing first.
- 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?
- Ask the municipality for flood maps.
- Are flood and wildfire insured?
- Is earthquake cover included?
What this data can and can’t tell you
- 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 Les Coteaux.
- 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 Les Coteaux.
- Earthquakes are modelled. The earthquake figure is an expected loss, not a forecast, worked out by NRCan for each census subdivision, Les Coteaux’s included.
- Radon is a survey. About 14,000 homes were tested across Canada in 2009–2011, and the share over the guideline for Les Coteaux is its health region’s, the survey’s design unit.
Questions about flooding and hazards in Les Coteaux
Does Les Coteaux flood?
The inventory has 0 studies for Les Coteaux, and an empty list isn’t a clean bill: the municipality holds any flood maps.
Is radon a problem in Les Coteaux?
The area’s survey found 8.2% of 110 tested homes above Health Canada’s guideline, so a three-month test is worth doing in Les Coteaux.
How big is the earthquake risk in Les Coteaux?
In NRCan’s seismic model, Les Coteaux’s buildings lose $0.16 per $1,000 of value in an average year.
How is Les Coteaux’s Hazard risk Grade worked out?
Hazard risk gives Les Coteaux C, weighing earthquakes and radon and counting wildfire only against it.
Is Les Coteaux at risk of wildfire?
Some, but Les Coteaux’s low band (0% of nearby land burned since 1986, latest 2024) is short of the level that counts.
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).