Photo: Veillg1 · CC0Coteau-du-Lac’s hazards at a glance: a low wildfire record and 8.2% of area homes over the radon guideline
No wildfire is mapped within 25 km of Coteau-du-Lac’s homes since 1986 (0% of the land, 0.001% a year). Seismic risk runs high: $0.14 of expected damage per $1,000 of buildings a year, the typical town $0.030. Coteau-du-Lac grades C for hazard risk; wildfire is low here, so it earns no credit.
What stands out about Coteau-du-Lac’s hazards
For Coteau-du-Lac, from NRCan’s seismic model, Health Canada’s radon survey, the national burned-area record and the flood map inventory.
What Coteau-du-Lac faces
Each hazard against its own yardstick; meters run from low to high on that yardstick.
Wildfire
Earthquakes
Radon
Flood study
Coteau-du-Lac grades C for hazard risk
Seismic risk and radon set Coteau-du-Lac’s grade, wildfire can drag it down, and flood mapping stays out of it.
Its place: #252 of 507 in Quebec and #2,204 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.
Wildfire is rare near Coteau-du-Lac: 0% of the land within 25 km burned since 1986, 0% within 5 km
Past fire around Coteau-du-Lac’s homes, from the national burned-area record, with the fuel within 5 km.
A burn rate of 0.001% a year keeps Coteau-du-Lac in the low band (the typical Canadian town: 0.000%).
The 5 km ring around Coteau-du-Lac’s homes is clear of burns since 1986, the nearest 6.0 km out.
Land that isn’t forest covers nearly all the ground around Coteau-du-Lac: forest fuel is 0.4% within 5 km and 2.8% within 25 km.
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
Coteau-du-Lac burns at 0.001% a year, 136th of 513 towns in Quebec; the leader, Mistissini, reaches 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.
The low band takes in 92% of Canada’s 2,610 towns, Coteau-du-Lac among them, though its rate is above zero; 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.
No flood study is listed for Coteau-du-Lac
What Canada’s Flood Map Inventory lists for Coteau-du-Lac: who studied flooding and where to see their maps.
NRCan’s inventory is silent on Coteau-du-Lac, so any flood map would be the municipality’s own.
Towns with a flood study on file
Coteau-du-Lac 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.
The grade leaves flood out, since a study area says nothing about how many of Coteau-du-Lac’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.”
High seismic risk in Coteau-du-Lac: $0.14 per $1,000 of buildings a year
Expected yearly building losses from earthquakes, from Natural Resources Canada’s model.
Coteau-du-Lac’s $0.14 is about 4.7 times the typical town’s $0.030: it sits in one of Canada’s more active seismic zones.
Shaking damage a year per $1,000 of building value
The median in Quebec is $0.14; Coteau-du-Lac, at $0.14, 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.
More earthquake risk than most: only 20% of Canada’s 2,611 towns are above Coteau-du-Lac.
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 Coteau-du-Lac 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 Coteau-du-Lac are over the radon guideline
Long-term radon tests in homes across the survey area, against Health Canada’s guideline.
Around Coteau-du-Lac, 8.2% of tested homes topped the guideline, near the typical Canadian town’s 6.6%.
Tested homes over 200 Bq/m³
Over 600 Bq/m³
Coteau-du-Lac’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.
Between 5% and 10% of tests over the guideline: Coteau-du-Lac, and 37% of Canada’s 2,611 towns; 26% are higher.
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.
Radon varies from house to house in Coteau-du-Lac, so the survey is a reason to test, not a result for yours.
Health Canada, Cross-Canada Survey of Radon Concentrations in Homes (2009–2011). · Radon tests: one figure for all of the Monteregie health region
Where to get warnings in Coteau-du-Lac
Environment and Climate Change Canada issues the weather alerts for Coteau-du-Lac; 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. |
Smoke and fire warnings for Coteau-du-Lac come through Environment Canada and Alert Ready; the fire map is CWFIS’s.
Weather alerts (ECCC) · Alert Ready · Fire danger and active fires (CWFIS)
How Coteau-du-Lac’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 |
|---|---|---|---|---|
| Coteau-du-Lac | Low | $0.14 | 8.2% | None listed |
| Les Coteaux 6,294 · 4.6 km | Low | $0.16 | 8.2% | None listed |
| Salaberry-de-Valleyfield 47,002 · 5.8 km | Low | $0.19 | 8.2% | None listed |
| Saint-Clet 1,784 · 6.7 km | Low | $0.18 | 8.2% | None listed |
| Les Cèdres 7,145 · 8.9 km | Low | $0.15 | 8.2% | None listed |
| Saint-Zotique 10,445 · 9.2 km | Low | $0.11 | 8.2% | None listed |
| Saint-Polycarpe 2,549 · 11 km | Low | $0.18 | 8.2% | None listed |
Coteau-du-Lac’s low band tops its neighbours; Les Coteaux is next (low).
Radon is the survey area’s figure, so neighbours in one area share it.
Get ready for what Coteau-du-Lac faces
Practical steps for Coteau-du-Lac’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
- Radon is a survey. About 14,000 homes were tested across Canada in 2009–2011, and the share over the guideline for Coteau-du-Lac is its health region’s, the survey’s design unit.
- Earthquakes are modelled. The earthquake figure is an expected loss, not a forecast, worked out by NRCan for each census subdivision, Coteau-du-Lac’s included.
- 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 Coteau-du-Lac.
- 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 Coteau-du-Lac.
Questions about flooding and hazards in Coteau-du-Lac
How big is the earthquake risk in Coteau-du-Lac?
NRCan’s model expects shaking to cost buildings in Coteau-du-Lac $0.14 a year for every $1,000 of their value, on average over many years.
Does Coteau-du-Lac flood?
No study on Canada’s Flood Map Inventory covers Coteau-du-Lac (0), which doesn’t mean it has never been mapped, so ask the municipality.
Is Coteau-du-Lac at risk of wildfire?
Not much by Canadian standards: Coteau-du-Lac’s band is low, with 0% of the land within 25 km burned since 1986 (last in 2024), so wildfire doesn’t change its grade.
How is Coteau-du-Lac’s Hazard risk Grade worked out?
Coteau-du-Lac’s Hazard risk grade is C, built on earthquakes and radon with a one-sided wildfire input.
Is radon a problem in Coteau-du-Lac?
8.2% of the 110 homes Health Canada tested around Coteau-du-Lac topped the guideline; your own house needs its own test.
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).