Photo: Gabriel Picard · CC BY-SA 4.0Saint-Louis’ hazards at a glance: a low wildfire record and 8.8% of area homes over the radon guideline
The national fire record shows next to nothing around Saint-Louis, 0% of the land within 25 km 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. Hazard risk gives Saint-Louis a grade of C−, from earthquakes and radon alone.
What stands out about Saint-Louis’s hazards
For Saint-Louis, from NRCan’s seismic model, Health Canada’s radon survey, the national burned-area record and the flood map inventory.
What Saint-Louis 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-Louis: C−
Seismic risk and radon set Saint-Louis’ grade, wildfire can drag it down, and flood mapping stays out of it.
Its place: #294 of 507 in Quebec and #2,256 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-Louis: 0% of the land within 25 km burned since 1986, 0% within 5 km
Fires mapped since 1986 around where Saint-Louis’ residents live, and the fuel next to their homes.
Forty years of fire maps put Saint-Louis at 0.000% a year, low next to the typical Canadian town’s 0.000%.
Saint-Louis’ homes have had no fire within 5 km since 1986; the closest was 21 km away.
The forest starts beyond town: 0.8% of the land within 5 km of Saint-Louis’ homes is forest fuel, against 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
Among the 513 towns in Quebec, Mistissini burns fastest (0.31% a year); Saint-Louis is with the 144 near zero.
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.
Saint-Louis shares the low band with 92% of Canada’s 2,610 towns, its burn rate rounding to nothing; 7.5% burn faster.
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.
No flood study is listed for Saint-Louis
Flood studies whose area touches Saint-Louis, from NRCan’s inventory, each linked to its owner.
An empty entry for Saint-Louis on the inventory isn’t proof of safety; ask locally for flood maps.
Towns with a flood study on file
Only 45% of towns in Quebec have a flood study, short of Canada’s 58%, and Saint-Louis is not among 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-Louis.
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.”
High seismic risk in Saint-Louis: $0.14 per $1,000 of buildings a year
NRCan’s seismic risk model: the damage shaking is expected to do to buildings each year, on average over many years.
Roughly 4.6 times the typical $0.030: Saint-Louis’ $0.14 marks real seismic exposure.
Nobody publishes earthquake risk for Saint-Louis alone, so this card uses the figure for the city of Québec.
Shaking damage a year per $1,000 of building value
Earthquake risk around Saint-Louis ($0.14) matches the middle in Quebec ($0.14), far from La Pocatière’s $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: 20% of its 2,611 towns expect more damage than Saint-Louis.
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-Louis 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).
Some radon around Saint-Louis: 8.8% of area homes over the guideline
Health Canada’s survey of long-term home tests: the share above the 200 Bq/m³ guideline.
Near the middle for radon: Saint-Louis’ area 8.8%, the typical Canadian town 6.6%. Behind radon tests sits data gathered across the Capitale-Nationale health region, with Saint-Louis one part of it.
Tested homes over 200 Bq/m³
Over 600 Bq/m³
2.5% of tests around Saint-Louis passed 600 Bq/m³; over 200, its 8.8% matches the median in Quebec, 8.2%.
Health Canada radon survey (2009–2011), by 2007 health region; medians of towns of 2,500 people or more.
Radon tops the guideline in a modest share of homes around Saint-Louis, a band holding 37% of Canada’s 2,611 towns; 26% rank above.
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.
Radon varies from house to house in Saint-Louis, so the survey is a reason to test, not a result for yours.
Health Canada, Cross-Canada Survey of Radon Concentrations in Homes (2009–2011).
Where to get warnings in Saint-Louis
Alerts for Saint-Louis 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-Louis 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)
How Saint-Louis’ neighbours compare on hazards
The same four hazards for the places next door.
| Town | Wildfire | Quake $/1,000 | Radon | Flood study |
|---|---|---|---|---|
| Saint-Louis | Low | $0.14 | 8.8% | None listed |
| Plateau 14,176 · 2.2 km | Low | $0.14 | 8.8% | Yes |
| Pointe-de-Sainte-Foy 14,541 · 2.5 km | Low | $0.14 | 8.8% | None listed |
| Cité-Universitaire 22,546 · 2.7 km | Low | $0.14 | 8.8% | Yes |
| Sillery 13,950 · 3.3 km | Low | $0.14 | 8.8% | None listed |
| Cap-Rouge 17,139 · 4.6 km | Low | $0.14 | 8.8% | None listed |
| Saint-Sacrement 10,650 · 4.9 km | Low | $0.14 | 8.8% | Yes |
The neighbour with the most fire is Plateau (low), still no more than Saint-Louis (low).
Radon is the survey area’s figure, so neighbours in one area share it.
Get ready for what Saint-Louis faces
Practical steps for Saint-Louis’ 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
- Earthquakes are modelled. The earthquake figure is an expected loss, not a forecast, worked out by NRCan for each census subdivision, Saint-Louis’ included.
- 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-Louis.
- 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-Louis.
- Radon is a survey. About 14,000 homes were tested across Canada in 2009–2011, and the share over the guideline for Saint-Louis is its health region’s, the survey’s design unit.
Questions about flooding and hazards in Saint-Louis
How is Saint-Louis’s Hazard risk Grade worked out?
Hazard risk gives Saint-Louis C−, weighing earthquakes and radon and counting wildfire only against it.
How big is the earthquake risk in Saint-Louis?
About $0.14 a year per $1,000 of building value, NRCan’s long-run expectation for Saint-Louis.
Is Saint-Louis at risk of wildfire?
Some, but Saint-Louis’ low band (0% of nearby land burned since 1986, latest 2022) is short of the level that counts.
Is radon a problem in Saint-Louis?
The area’s survey found 8.8% of 160 tested homes above Health Canada’s guideline, so a three-month test is worth doing in Saint-Louis.
Does Saint-Louis flood?
The inventory has 0 studies for Saint-Louis, and an empty list isn’t a clean bill: the municipality holds any flood maps.
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).