Photo: Noppen, Luc, 1949 · CC BY-SA 4.0Saint-Joseph-du-Lac is on Canada’s flood inventory: 1 listed, led by Communauté métropolitaine de Montréal
Burn scars are few around Saint-Joseph-du-Lac, with 0% of the land within 25 km touched by fire since 1986 (0.000% a year). Seismic risk runs high: $0.14 of expected damage per $1,000 of buildings a year, the typical town $0.030. More homes than usual carry radon here, 10% over the guideline where the typical town has 6.6%. Hazard risk gives Saint-Joseph-du-Lac a grade of C−, from earthquakes and radon alone.
What stands out about Saint-Joseph-du-Lac’s hazards
Four national sources, each read for Saint-Joseph-du-Lac: earthquakes, radon, past fires and flood studies.
What Saint-Joseph-du-Lac faces
Each hazard against its own yardstick; meters run from low to high on that yardstick.
Wildfire
Earthquakes
Radon
Flood study
Saint-Joseph-du-Lac grades C− for hazard risk
For Saint-Joseph-du-Lac, Risk will be the average of earthquakes and radon, with wildfire added only if it makes the average worse.
Its place: #413 of 507 in Quebec and #2,399 of 2,589 Canadian towns.
How sure: Earthquake losses are a model’s expectation over many years, not a forecast for any one. The radon share rests on 78 home tests in the survey area, so a few homes move it. Small fires and grass fires are largely missing from the national burned-area record.
Few fires near Saint-Joseph-du-Lac: 0% within 5 km, 0% within 25 km
Fires mapped since 1986 around where Saint-Joseph-du-Lac’s residents live, and the fuel next to their homes.
Forty years of fire maps put Saint-Joseph-du-Lac at 0.000% a year, low next to the typical Canadian town’s 0.000%.
Forest makes up 1.1% of the land within 5 km of Saint-Joseph-du-Lac and 4.7% within 25 km, little for a forest fire to run through.
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
To three decimals the burn rate around Saint-Joseph-du-Lac is zero, as for 144 of the 513 towns in Quebec, while 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.
92% of Canada’s 2,610 towns are in the low band and 7.5% above it; Saint-Joseph-du-Lac is among the many where the yearly burn rate rounds to zero.
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.
A flood study covers Saint-Joseph-du-Lac, from Communauté métropolitaine de Montréal: 1 on the inventory
Flood studies whose area touches Saint-Joseph-du-Lac, from NRCan’s inventory, each linked to its owner.
For Saint-Joseph-du-Lac the inventory points to Communauté métropolitaine de Montréal’s 2008 study, whose map is the one to check.
| Study | By | Year | Status |
|---|---|---|---|
| Montréal-Argenteuil-Deux-Montagnes-Vaudreuil-Soulanges | Communauté métropolitaine de Montréal | 2008 | final |
Towns with a flood study on file
Saint-Joseph-du-Lac 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 Saint-Joseph-du-Lac 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 Saint-Joseph-du-Lac’s costliest hazard: $0.14 a year per $1,000
NRCan’s seismic risk model: the damage shaking is expected to do to buildings each year, on average over many years.
Roughly 4.5 times the typical $0.030: Saint-Joseph-du-Lac’s $0.14 marks real seismic exposure.
Shaking damage a year per $1,000 of building value
Shaking damage around Saint-Joseph-du-Lac runs at $0.14 a year, near the $0.14 of the typical town in Quebec; La Pocatière has $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.
Saint-Joseph-du-Lac sits above most of Canada’s 2,611 towns on earthquake risk; 22% are higher.
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 model counts damage to Saint-Joseph-du-Lac’s buildings and their occupants from shaking only: not liquefaction, landslides, tsunami or fires after a quake.
Natural Resources Canada, Canada’s Seismic Risk Model (2022), by census subdivision (2016 boundaries; a few 2021 subdivisions take their residents’ mean).
10% of homes tested around Saint-Joseph-du-Lac are over the radon guideline
Health Canada’s survey of long-term home tests: the share above the 200 Bq/m³ guideline.
A higher share than most: 10% of tested homes around Saint-Joseph-du-Lac, the typical Canadian town 6.6%.
Tested homes over 200 Bq/m³
Over 600 Bq/m³
More homes top the guideline around Saint-Joseph-du-Lac (10%) than in the typical town in Quebec (8.2%); 1.3% went over 600.
Health Canada radon survey (2009–2011), by 2007 health region; medians of towns of 2,500 people or more.
4.6% of Canada’s 2,611 towns have a higher share of homes over 200 Bq/m³ than Saint-Joseph-du-Lac, in the 10–20% band with 22%.
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.
Basements, soil and how a house is sealed decide its radon, so in Saint-Joseph-du-Lac only a test can say.
Health Canada, Cross-Canada Survey of Radon Concentrations in Homes (2009–2011). · Not measured by town: radon tests (the Laurentides health region)
Weather and fire alerts for Saint-Joseph-du-Lac
Alerts for Saint-Joseph-du-Lac 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-Joseph-du-Lac to phones; CWFIS shows the day’s fire danger.
Weather alerts (ECCC) · Alert Ready · Fire danger and active fires (CWFIS)
Hazards in the places around Saint-Joseph-du-Lac
The same four hazards for the places next door.
| Town | Wildfire | Quake $/1,000 | Radon | Flood study |
|---|---|---|---|---|
| Saint-Joseph-du-Lac | Low | $0.14 | 10% | Yes |
| Pointe-Calumet 6,427 · 2.8 km | Low | $0.15 | 10% | Yes |
| Sainte-Marthe-sur-le-Lac 21,949 · 4.4 km | Low | $0.19 | 10% | Yes |
| Oka 4,312 · 6.7 km | Low | $0.13 | 10% | Yes |
| Deux-Montagnes 18,516 · 7.8 km | Low | $0.20 | 10% | Yes |
| L'Île-Bizard–Sainte-Geneviève 18,885 · 9.2 km | Low | $0.20 | 6.8% | Yes |
| Saint-Eustache 47,562 · 9.5 km | Low | $0.20 | 10% | Yes |
The fire record around Sainte-Marthe-sur-le-Lac is a touch heavier than Saint-Joseph-du-Lac’s, but the band is the same: low (here low).
Radon is the survey area’s figure, so neighbours in one area share it.
Get ready for what Saint-Joseph-du-Lac faces
Practical steps for Saint-Joseph-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?
- 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-Joseph-du-Lac.
- Earthquakes are modelled. Shaking damage is modelled from the ground, the buildings and the odds of each quake, and published for whole subdivisions such as Saint-Joseph-du-Lac’s.
- Wildfire counts one way. The wildfire figure is the share of land within 25 km of Saint-Joseph-du-Lac’s homes burned each year from 1986 to 2025, past fire rather than a forecast, and it can only lower Risk.
- Radon is a survey. Health Canada’s survey tested some 14,000 homes over three months; until postal-area boundaries are loaded, Saint-Joseph-du-Lac takes its 2007 health region’s share.
Questions about flooding and hazards in Saint-Joseph-du-Lac
How big is the earthquake risk in Saint-Joseph-du-Lac?
Expected earthquake damage in Saint-Joseph-du-Lac comes to $0.14 a year for each $1,000 that buildings are worth.
Does Saint-Joseph-du-Lac flood?
The inventory lists a study touching Saint-Joseph-du-Lac; whether a given street floods is on that map, not in the grade.
How is Saint-Joseph-du-Lac’s Hazard risk Grade worked out?
Saint-Joseph-du-Lac grades C− for hazard risk, from earthquakes and radon, with wildfire counted only where it lowers the grade.
Is Saint-Joseph-du-Lac at risk of wildfire?
Some, but Saint-Joseph-du-Lac’s low band (0% of nearby land burned since 1986, latest 2025) is short of the level that counts.
Is radon a problem in Saint-Joseph-du-Lac?
The area’s survey found 10% of 78 tested homes above Health Canada’s guideline, so a three-month test is worth doing in Saint-Joseph-du-Lac.
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).