Photo: Groupe de recherche en art du Québec · CC BY-SA 4.0Flood mapping exists for Beauharnois: 1 on record, latest by Gouvernement du Québec
Little of the land around Beauharnois has burned: 0.1% within 25 km since 1986, or 0.002% a year. Seismic risk runs high: $0.18 of expected damage per $1,000 of buildings a year, the typical town $0.030. Radon is about average around Beauharnois: 8.2% of tested homes in the survey area topped the guideline, against 6.6% for the typical town. Beauharnois grades C− for hazard risk; wildfire is low here, so it earns no credit.
What stands out about Beauharnois’s hazards
For Beauharnois, from NRCan’s seismic model, Health Canada’s radon survey, the national burned-area record and the flood map inventory.
What Beauharnois faces
Each hazard against its own yardstick; meters run from low to high on that yardstick.
Wildfire
Earthquakes
Radon
Flood study
Beauharnois grades C− for hazard risk
Earthquake risk and radon make Beauharnois’ grade; wildfire can only lower it, never raise it, and flood studies are listed but not scored.
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. The burned-area record misses fires under about 10 ha and most grass and farm fires.
Few fires near Beauharnois: 0% within 5 km, 0.1% within 25 km
Past fire around Beauharnois’ homes, from the national burned-area record, with the fuel within 5 km.
The yearly burn rate around Beauharnois is 0.002%, low beside 0.000% for the typical Canadian town.
The closest burn since 1986 lies 7.1 km from Beauharnois’ homes, none within 5 km.
Land that isn’t forest covers nearly all the ground around Beauharnois: forest fuel is 1.9% 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
In the top quarter in Quebec: Beauharnois 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.
The low band takes in 92% of Canada’s 2,610 towns, Beauharnois 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.
Gouvernement du Québec has mapped flooding for Beauharnois (1 study)
What Canada’s Flood Map Inventory lists for Beauharnois: who studied flooding and where to see their maps.
Gouvernement du Québec holds the flood mapping that covers Beauharnois (1977), linked below.
| Study | By | Year | Status |
|---|---|---|---|
| St-Louis-Varennes | Gouvernement du Québec | 1977 | final |
Towns with a flood study on file
Beauharnois is one of the 45% of towns in Quebec with a flood study on file, fewer than Canada’s 58%.
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 Beauharnois 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.”
Natural Resources Canada, Canada Flood Map Inventory; links go to each study’s owner.
Shaking is Beauharnois’ costliest hazard: $0.18 a year per $1,000
Expected yearly building losses from earthquakes, from Natural Resources Canada’s model.
Beauharnois’ $0.18 is about 6 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
At $0.18, Beauharnois is above the typical town in Quebec ($0.14); La Pocatière has the most 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.
In the upper part of Canada’s range: 13% of its 2,611 towns expect more damage than Beauharnois.
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).
What a quake does after the shaking, fire, landslides, tsunami, falls outside NRCan’s figure for Beauharnois.
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 Beauharnois: 8.2% of area homes over the guideline
Long-term radon tests in homes across the survey area, against Health Canada’s guideline. · Radon tests for the Monteregie health region
Beauharnois’ 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
The typical town in Quebec has 8.2% over 200 Bq/m³; Beauharnois’ area has 8.2%, much the same.
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 Beauharnois’ 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.
Whatever Beauharnois’ area share, the reading that matters is your own home’s, over a winter.
Health Canada, Cross-Canada Survey of Radon Concentrations in Homes (2009–2011).
Where to get warnings in Beauharnois
Alerts for Beauharnois 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 Beauharnois to phones; CWFIS shows the day’s fire danger.
Weather alerts (ECCC) · Alert Ready · Fire danger and active fires (CWFIS)
How Beauharnois’ neighbours compare on hazards
Wildfire band, earthquake risk, radon and flood studies for each place nearby.
| Town | Wildfire | Quake $/1,000 | Radon | Flood study |
|---|---|---|---|---|
| Beauharnois | Low | $0.18 | 8.2% | Yes |
| Saint-Étienne-de-Beauharnois 1,151 · 7.2 km | Low | $0.18 | 8.2% | None listed |
| Léry 2,817 · 7.5 km | Low | $0.16 | 8.2% | Yes |
| Pointe-des-Cascades 1,867 · 8.1 km | Low | $0.14 | 8.2% | Yes |
| Sainte-Martine 5,884 · 8.8 km | Low | $0.19 | 8.2% | Yes |
| Notre-Dame-de-l'Île-Perrot 11,716 · 8.9 km | Low | $0.14 | 8.2% | Yes |
| Mercier 16,036 · 11 km | Low | $0.19 | 8.2% | Yes |
Nowhere around Beauharnois burns more: Saint-Étienne-de-Beauharnois, the closest rival, is low to its low.
Radon is the survey area’s figure, so neighbours in one area share it.
Get ready for what Beauharnois faces
Practical steps for Beauharnois’ 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. NRCan’s inventory says where flood mapping exists, not where water goes; the map’s owner is the authority for Beauharnois.
- 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 Beauharnois.
- Radon is a survey. About 14,000 homes were tested across Canada in 2009–2011, and the share over the guideline for Beauharnois 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, Beauharnois’ included.
Questions about flooding and hazards in Beauharnois
How big is the earthquake risk in Beauharnois?
In NRCan’s seismic model, Beauharnois’ buildings lose $0.18 per $1,000 of value in an average year.
Does Beauharnois flood?
There is flood mapping for Beauharnois on the national inventory, each study linked to its owner’s map, none of them graded.
Is radon a problem in Beauharnois?
8.2% of the 110 homes Health Canada tested around Beauharnois topped the guideline; your own house needs its own test.
Is Beauharnois at risk of wildfire?
Not much by Canadian standards: Beauharnois’ band is low, with 0.1% of the land within 25 km burned since 1986 (last in 2025), so wildfire doesn’t change its grade.
How is Beauharnois’s Hazard risk Grade worked out?
Hazard risk gives Beauharnois 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).