Photo: Veillg1 · CC BY-SA 4.0A flood study covers Saint-Basile-le-Grand: 1 on the national inventory, the newest from Gouvernement du Québec
Little of the land around Saint-Basile-le-Grand has burned: 0.1% within 25 km since 1986, or 0.002% a year. Earthquakes add more: NRCan’s model puts building losses at $0.18 a year per $1,000 of value, against $0.030 for the typical town. In Health Canada’s survey, 8.2% of homes tested in Saint-Basile-le-Grand’s area exceeded 200 Bq/m³, close to the typical 6.6%. Saint-Basile-le-Grand grades C− for hazard risk; wildfire is low here, so it earns no credit.
What stands out about Saint-Basile-le-Grand’s hazards
Four national sources, each read for Saint-Basile-le-Grand: earthquakes, radon, past fires and flood studies.
What Saint-Basile-le-Grand faces
Each hazard against its own yardstick; meters run from low to high on that yardstick.
Wildfire
Earthquakes
Radon
Flood study
Hazard risk in Saint-Basile-le-Grand: C−
For Saint-Basile-le-Grand, Risk will be the average of earthquakes and radon, with wildfire added only if it makes the average worse.
Its place: #331 of 507 in Quebec and #2,295 of 2,589 Canadian towns.
How sure: Earthquake losses are a model’s expectation over many years, not a forecast for any one. Small fires and grass fires are largely missing from the national burned-area record.
Wildfire is rare near Saint-Basile-le-Grand: 0.1% of the land within 25 km burned since 1986, 0% within 5 km
Fires mapped since 1986 around where Saint-Basile-le-Grand’s residents live, and the fuel next to their homes.
At 0.002% of the land a year, Saint-Basile-le-Grand’s burn rate is in the low band; the typical Canadian town sees 0.000%.
The closest burn since 1986 lies 9.9 km from Saint-Basile-le-Grand’s homes, none within 5 km.
With 0.5% forest fuel within 5 km and 1.2% within 25 km, the land around Saint-Basile-le-Grand 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
In the top quarter in Quebec: Saint-Basile-le-Grand 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.
Low, like 92% of the country’s 2,610 towns: the land around Saint-Basile-le-Grand burns, but slower than in the 7.5% above it.
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 Saint-Basile-le-Grand (1 study)
Flood studies whose area touches Saint-Basile-le-Grand, from NRCan’s inventory, each linked to its owner.
For Saint-Basile-le-Grand the inventory points to Gouvernement du Québec’s 1979 study, whose map is the one to check.
| Study | By | Year | Status |
|---|---|---|---|
| Sorel-Chambly | Gouvernement du Québec | 1979 | final |
Towns with a flood study on file
Only 45% of towns in Quebec have a flood study, short of Canada’s 58%; Saint-Basile-le-Grand is one of them.
NRCan Canada Flood Map Inventory: a study footprint touching the town’s boundary; towns of 2,500 people or more.
Flood studies don’t enter the grade; they are listed so you can open the official map for Saint-Basile-le-Grand.
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.
Earthquakes cost buildings in Saint-Basile-le-Grand $0.18 per $1,000 a year
NRCan’s seismic risk model: the damage shaking is expected to do to buildings each year, on average over many years.
Roughly 6 times the typical $0.030: Saint-Basile-le-Grand’s $0.18 marks real seismic exposure.
Shaking damage a year per $1,000 of building value
The typical town in Quebec expects $0.14 a year; Saint-Basile-le-Grand expects $0.18, and La Pocatière $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 13% of Canada’s 2,611 towns are above Saint-Basile-le-Grand.
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).
The loss is to Saint-Basile-le-Grand’s buildings alone, from ground shaking; infrastructure and secondary hazards are left out.
Natural Resources Canada, Canada’s Seismic Risk Model (2022), by census subdivision (2016 boundaries; a few 2021 subdivisions take their residents’ mean).
Some radon around Saint-Basile-le-Grand: 8.2% of area homes over the guideline
Health Canada’s survey of long-term home tests: the share above the 200 Bq/m³ guideline.
Saint-Basile-le-Grand’s area sits close to the typical Canadian town: 8.2% over the guideline, against 6.6%.
Tested homes over 200 Bq/m³
Over 600 Bq/m³
Around Saint-Basile-le-Grand, 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.
Between 5% and 10% of tests over the guideline: Saint-Basile-le-Grand, 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.
The survey sampled homes around Saint-Basile-le-Grand; it can’t tell you your basement’s level.
Health Canada, Cross-Canada Survey of Radon Concentrations in Homes (2009–2011). · Not measured by town: radon tests (the Monteregie health region)
Weather and fire alerts for Saint-Basile-le-Grand
Alerts for Saint-Basile-le-Grand 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. |
Evacuation orders for Saint-Basile-le-Grand come from the municipality or the province, while CWFIS maps fire danger every day.
Weather alerts (ECCC) · Alert Ready · Fire danger and active fires (CWFIS)
Hazards in the places around Saint-Basile-le-Grand
The same four hazards for the places next door.
| Town | Wildfire | Quake $/1,000 | Radon | Flood study |
|---|---|---|---|---|
| Saint-Basile-le-Grand | Low | $0.18 | 8.2% | Yes |
| Saint-Bruno-de-Montarville 26,786 · 3.9 km | Low | $0.16 | 8.2% | None listed |
| McMasterville 6,114 · 5.2 km | Low | $0.18 | 8.2% | Yes |
| Saint-Mathias-sur-Richelieu 4,598 · 5.6 km | Low | $0.18 | 8.2% | Yes |
| Otterburn Park 9,460 · 6.9 km | Low | $0.13 | 8.2% | Yes |
| Sainte-Julie 30,981 · 8.2 km | Low | $0.19 | 8.2% | None listed |
| Beloeil 25,240 · 8.3 km | Low | $0.20 | 8.2% | Yes |
None of the places around has more fire nearby than Saint-Basile-le-Grand (low); Saint-Bruno-de-Montarville comes closest (low).
Radon is the survey area’s figure, so neighbours in one area share it.
Get ready for what Saint-Basile-le-Grand faces
Practical steps for Saint-Basile-le-Grand’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?
- 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. Wildfire is read from the national burned-area record around Saint-Basile-le-Grand’s homes since 1986, a history of fire that may lower Risk but never raises it.
- 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 Saint-Basile-le-Grand.
- Earthquakes are modelled. NRCan models what earthquakes would cost buildings each year on average, subdivision by subdivision; Saint-Basile-le-Grand’s figure is its subdivision’s.
- Radon is a survey. About 14,000 homes were tested across Canada in 2009–2011, and the share over the guideline for Saint-Basile-le-Grand is its health region’s, the survey’s design unit.
Questions about flooding and hazards in Saint-Basile-le-Grand
Does Saint-Basile-le-Grand flood?
There is flood mapping for Saint-Basile-le-Grand on the national inventory, each study linked to its owner’s map, none of them graded.
How big is the earthquake risk in Saint-Basile-le-Grand?
Expected earthquake damage in Saint-Basile-le-Grand comes to $0.18 a year for each $1,000 that buildings are worth.
Is Saint-Basile-le-Grand at risk of wildfire?
Some, but Saint-Basile-le-Grand’s low band (0.1% of nearby land burned since 1986, latest 2024) is short of the level that counts.
Is radon a problem in Saint-Basile-le-Grand?
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 Saint-Basile-le-Grand.
How is Saint-Basile-le-Grand’s Hazard risk Grade worked out?
Hazard risk gives Saint-Basile-le-Grand 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).