Photo: Pymouss · CC BY-SA 4.0Flood mapping exists for Saint-Constant: 4 on record, latest by Gouvernement du Québec
Fire seldom reaches Saint-Constant: since 1986, 0% of the land within 25 km has burned (0.001% a year). Seismic risk runs high: $0.22 of expected damage per $1,000 of buildings a year, the typical town $0.030. Radon is about average around Saint-Constant: 8.2% of tested homes in the survey area topped the guideline, against 6.6% for the typical town. Hazard risk gives Saint-Constant a grade of C−, from earthquakes and radon alone.
What stands out about Saint-Constant’s hazards
For Saint-Constant, from NRCan’s seismic model, Health Canada’s radon survey, the national burned-area record and the flood map inventory.
What Saint-Constant faces
Each hazard against its own yardstick; meters run from low to high on that yardstick.
Wildfire
Earthquakes
Radon
Flood study
Saint-Constant grades C− for hazard risk
Seismic risk and radon set Saint-Constant’s grade, wildfire can drag it down, and flood mapping stays out of it.
Its place: #379 of 507 in Quebec and #2,358 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 Saint-Constant: 0% of the land within 25 km burned since 1986, 0.1% within 5 km
Past fire around Saint-Constant’s homes, from the national burned-area record, with the fuel within 5 km.
The land within 25 km of Saint-Constant burns at 0.001% a year on average, the low band; the typical Canadian town: 0.000%.
Land that isn’t forest covers nearly all the ground around Saint-Constant: forest fuel is 0.8% within 5 km and 1.1% 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
Saint-Constant 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.
Some fire is mapped around Saint-Constant, but not enough to leave the low band, where 92% of Canada’s 2,610 towns are; 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.
Flooding around Saint-Constant is mapped in 4 studies, the newest by Gouvernement du Québec
What Canada’s Flood Map Inventory lists for Saint-Constant: who studied flooding and where to see their maps.
The newest of 4 studies covering Saint-Constant is Gouvernement du Québec’s, from 2008; open its map to see the zones.
| Study | By | Year | Status |
|---|---|---|---|
| St-Constant | Gouvernement du Québec | 2008 | final |
| St-Constant-St-Isidore | Gouvernement du Québec | 2008 | final |
| Roussillon-St-Régis-St-Pierre-Portage | MRC Roussillon | 2001 | final |
| Roussillon-Tortue | MRC Roussillon | 2000 | final |
Towns with a flood study on file
Flood maps are thinner in Quebec, 45% of towns against 58% nationally, but Saint-Constant has one.
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-Constant.
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 Saint-Constant’s costliest hazard: $0.22 a year per $1,000
Expected yearly building losses from earthquakes, from Natural Resources Canada’s model.
Roughly 7.3 times the typical $0.030: Saint-Constant’s $0.22 marks real seismic exposure.
Shaking damage a year per $1,000 of building value
Above the middle in Quebec: Saint-Constant’s $0.22 against a median of $0.14, with La Pocatière 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.
Only 7.5% of Canada’s 2,611 towns expect more shaking damage than Saint-Constant.
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 Saint-Constant 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).
Some radon around Saint-Constant: 8.2% 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 Monteregie health region: radon tests
Saint-Constant’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
Around Saint-Constant, 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.
37% of Canada’s 2,611 towns share Saint-Constant’s band of 5 to 10%; 26% sit 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.
Health Canada advises testing every home, Saint-Constant’s included, whatever the area’s figure.
Health Canada, Cross-Canada Survey of Radon Concentrations in Homes (2009–2011).
Where to get warnings in Saint-Constant
Alerts for Saint-Constant 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 Saint-Constant 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)
Hazards in the places around Saint-Constant
Wildfire band, earthquake risk, radon and flood studies for each place nearby.
| Town | Wildfire | Quake $/1,000 | Radon | Flood study |
|---|---|---|---|---|
| Saint-Constant | Low | $0.22 | 8.2% | Yes |
| Sainte-Catherine 17,782 · 2.5 km | Low | $0.22 | 8.2% | Yes |
| Delson 8,802 · 2.5 km | Low | $0.21 | 8.2% | Yes |
| Candiac 24,920 · 5.4 km | Low | $0.20 | 8.2% | Yes |
| Sault-Saint-Louis 47,270 · 6.5 km | Low | $0.20 | 6.8% | None listed |
| Cecil-P.-Newman 34,965 · 7.2 km | Low | $0.20 | 6.8% | None listed |
| Desmarchais-Crawford 18,505 · 7.7 km | Low | $0.20 | 6.8% | None listed |
Saint-Constant’s low band tops its neighbours; Sainte-Catherine is next (low).
Radon is the survey area’s figure, so neighbours in one area share it.
Get ready for what Saint-Constant faces
Practical steps for Saint-Constant’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
- Flood studies aren’t flood zones. The flood inventory points to maps; it is incomplete and not the official source, so ask the municipality about any street in Saint-Constant.
- Radon is a survey. Health Canada’s survey tested some 14,000 homes over three months; until postal-area boundaries are loaded, Saint-Constant takes its 2007 health region’s share.
- Earthquakes are modelled. Seismic risk is NRCan’s model of yearly building losses from shaking, averaged over many years and given for Saint-Constant’s census subdivision (a neighbourhood shows its city’s).
- Wildfire counts one way. For Saint-Constant, wildfire means how much nearby land burned in the past forty years, a one-way input that can pull Risk down and nothing more.
Questions about flooding and hazards in Saint-Constant
How big is the earthquake risk in Saint-Constant?
NRCan’s model expects shaking to cost buildings in Saint-Constant $0.22 a year for every $1,000 of their value, on average over many years.
Does Saint-Constant flood?
The inventory lists a study touching Saint-Constant; whether a given street floods is on that map, not in the grade.
How is Saint-Constant’s Hazard risk Grade worked out?
Hazard risk gives Saint-Constant C−, weighing earthquakes and radon and counting wildfire only against it.
Is radon a problem in Saint-Constant?
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-Constant.
Is Saint-Constant at risk of wildfire?
Some, but Saint-Constant’s low band (0% of nearby land burned since 1986, latest 2025) 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).