Photo: Bernard Gagnon · CC BY-SA 3.0Hazards in Saint-Étienne-des-Grès: wildfire low, radon over the guideline in 0% of tested homes
Little of the land around Saint-Étienne-des-Grès has burned: 0.1% within 25 km since 1986, or 0.002% a year. Seismic risk runs high: $0.11 of expected damage per $1,000 of buildings a year, the typical town $0.030. Saint-Étienne-des-Grès grades B+ for hazard risk, with wildfire counted against it.
What stands out about Saint-Étienne-des-Grès’s hazards
For Saint-Étienne-des-Grès, from NRCan’s seismic model, Health Canada’s radon survey, the national burned-area record and the flood map inventory.
What Saint-Étienne-des-Grès faces
Each hazard against its own yardstick; meters run from low to high on that yardstick.
Wildfire
Earthquakes
Radon
Flood study
Saint-Étienne-des-Grès grades B+ for hazard risk
Seismic risk and radon set Saint-Étienne-des-Grès’ grade, wildfire can drag it down, and flood mapping stays out of it.
Its place: #26 of 507 in Quebec and #911 of 2,589 Canadian towns.
How sure: The seismic figure is a long-run average from NRCan’s model, not a prediction. Only 58 homes were tested in the survey area, so the radon share is rough. The burned-area record misses fires under about 10 ha and most grass and farm fires.
Few fires near Saint-Étienne-des-Grès: 0.2% within 5 km, 0.1% within 25 km
Past fire around Saint-Étienne-des-Grès’ homes, from the national burned-area record, with the fuel within 5 km.
With 0.002% burned a year, Saint-Étienne-des-Grès is among the many low-band places (the typical Canadian town 0.000%).
Forest fuel is denser close to Saint-Étienne-des-Grès (33% within 5 km) than further out (23% 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
In the top quarter in Quebec: Saint-Étienne-des-Grès ranks 35th of 513 at 0.002% a year, with Mistissini first 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.
Beside 2,610 Canadian towns, Saint-Étienne-des-Grès 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.
The flood map inventory lists nothing for Saint-Étienne-des-Grès
What Canada’s Flood Map Inventory lists for Saint-Étienne-des-Grès: who studied flooding and where to see their maps.
The inventory has nothing for Saint-Étienne-des-Grès, but a local or conservation-authority map may still exist.
Towns with a flood study on file
Flood maps are thinner in Quebec, 45% of towns against 58% nationally, and Saint-Étienne-des-Grès has none.
NRCan Canada Flood Map Inventory: a study footprint touching the town’s boundary; towns of 2,500 people or more.
Listed, not scored: a flood study proves a map exists, not that Saint-Étienne-des-Grès floods.
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.”
Shaking is Saint-Étienne-des-Grès’ costliest hazard: $0.11 a year per $1,000
Expected yearly building losses from earthquakes, from Natural Resources Canada’s model.
Roughly 3.6 times the typical $0.030: Saint-Étienne-des-Grès’ $0.11 marks real seismic exposure.
Shaking damage a year per $1,000 of building value
The typical town in Quebec expects $0.14 a year in shaking damage; Saint-Étienne-des-Grès expects less, $0.11, and La Pocatière the most, $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: 25% of its 2,611 towns expect more damage than Saint-Étienne-des-Grès.
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 Saint-Étienne-des-Grès 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).
Little radon around Saint-Étienne-des-Grès: 0% of area homes over the guideline
Long-term radon tests in homes across the survey area, against Health Canada’s guideline. · Shared with the rest of the Mauricie et Centre-du-Quebec health region: radon tests
Saint-Étienne-des-Grès’ area, at 0%, is below the 6.6% of the typical Canadian town, though any one home can still be high.
Tested homes over 200 Bq/m³
Over 600 Bq/m³
Against the typical town in Quebec (8.2%), the area around Saint-Étienne-des-Grès has fewer high tests: 0%.
Health Canada radon survey (2009–2011), by 2007 health region; medians of towns of 2,500 people or more.
Under 5% puts Saint-Étienne-des-Grès with 37% of Canada’s 2,611 towns; 63% have more high tests.
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, Saint-Étienne-des-Grès’ included, whatever the area’s figure.
Health Canada, Cross-Canada Survey of Radon Concentrations in Homes (2009–2011).
Where to get warnings in Saint-Étienne-des-Grès
Alerts for Saint-Étienne-des-Grès 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. |
Alert Ready carries evacuation orders for Saint-Étienne-des-Grès to phones; CWFIS shows the day’s fire danger.
Weather alerts (ECCC) · Alert Ready · Fire danger and active fires (CWFIS)
How Saint-Étienne-des-Grès’ neighbours compare on hazards
Wildfire band, earthquake risk, radon and flood studies for each place nearby.
| Town | Wildfire | Quake $/1,000 | Radon | Flood study |
|---|---|---|---|---|
| Saint-Étienne-des-Grès | Low | $0.11 | 0% | None listed |
| Saint-Barnabé 1,234 · 7.3 km | Low | $0.12 | 0% | None listed |
| Saint-Boniface 5,405 · 8.4 km | Low | $0.090 | 0% | Yes |
| Notre-Dame-du-Mont-Carmel 6,613 · 9.4 km | Low | $0.098 | 0% | None listed |
| Charette 1,178 · 10.0 km | Low | $0.10 | 0% | None listed |
| Saint-Élie-de-Caxton 2,062 · 14 km | Low | $0.076 | 0% | None listed |
| Shawinigan 51,739 · 16 km | Low | $0.090 | 0% | Yes |
Shawinigan burns a little more than Saint-Étienne-des-Grès, 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 Saint-Étienne-des-Grès faces
Practical steps for Saint-Étienne-des-Grès’ 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. A study’s area can be a whole watershed or province, so being on the inventory says a map exists, not that a home in Saint-Étienne-des-Grès floods.
- Earthquakes are modelled. The earthquake figure is an expected loss, not a forecast, worked out by NRCan for each census subdivision, Saint-Étienne-des-Grès’ included.
- Radon is a survey. The radon share comes from about 14,000 long-term home tests in 2009–2011, pooled for now by the 2007 health region Saint-Étienne-des-Grès sits in.
- 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 Saint-Étienne-des-Grès.
Questions about flooding and hazards in Saint-Étienne-des-Grès
Does Saint-Étienne-des-Grès flood?
The inventory has 0 studies for Saint-Étienne-des-Grès, and an empty list isn’t a clean bill: the municipality holds any flood maps.
How is Saint-Étienne-des-Grès’s Hazard risk Grade worked out?
Saint-Étienne-des-Grès’ Hazard risk grade is B+, built on earthquakes and radon with a one-sided wildfire input.
How big is the earthquake risk in Saint-Étienne-des-Grès?
NRCan’s model expects shaking to cost buildings in Saint-Étienne-des-Grès $0.11 a year for every $1,000 of their value, on average over many years.
Is radon a problem in Saint-Étienne-des-Grès?
The area’s survey found 0% of 58 tested homes above Health Canada’s guideline, so a three-month test is worth doing in Saint-Étienne-des-Grès.
Is Saint-Étienne-des-Grès at risk of wildfire?
Some, but Saint-Étienne-des-Grès’ low band (0.1% 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).