Photo: Interaction Qui Ltée · Public domainHazards in Saint-Ambroise: wildfire low, radon over the guideline in 2.8% of tested homes
Burn scars are few around Saint-Ambroise, with 0.3% of the land within 25 km touched by fire since 1986 (0.008% a year). Seismic risk runs high: $0.22 of expected damage per $1,000 of buildings a year, the typical town $0.030. Hazard risk gives Saint-Ambroise a grade of C+; its wildfire band pulls it down.
What stands out about Saint-Ambroise’s hazards
Four national sources, each read for Saint-Ambroise: earthquakes, radon, past fires and flood studies.
What Saint-Ambroise faces
Each hazard against its own yardstick; meters run from low to high on that yardstick.
Wildfire
Earthquakes
Radon
Flood study
Saint-Ambroise grades C+ for hazard risk
Seismic risk and radon set Saint-Ambroise’s grade, wildfire can drag it down, and flood mapping stays out of it.
Its place: #105 of 507 in Quebec and #1,784 of 2,589 Canadian towns.
How sure: The seismic figure is a long-run average from NRCan’s model, not a prediction. The radon share rests on 72 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.
Little of the land around Saint-Ambroise has burned: 0% within 5 km, 0.3% within 25 km since 1986
Fires mapped since 1986 around where Saint-Ambroise’s residents live, and the fuel next to their homes.
Fire claims 0.008% of the land around Saint-Ambroise each year, a low band, with the typical Canadian town at 0.000%.
The 5 km ring around Saint-Ambroise’s homes is clear of burns since 1986, the nearest 10 km out.
Forest fuel covers 56% of the land close to Saint-Ambroise and 61% across 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-Ambroise ranks 21st of the 513 towns in Quebec for burn rate, at 0.008% a year; Mistissini leads with 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.
7.5% of Canada’s 2,610 towns burn fast enough to rank moderate or above; Saint-Ambroise stays low, with 92%.
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.
The flood map inventory lists nothing for Saint-Ambroise
Flood studies whose area touches Saint-Ambroise, from NRCan’s inventory, each linked to its owner.
There is no study for Saint-Ambroise on the national flood inventory, which is far from complete.
Towns with a flood study on file
Saint-Ambroise has no flood study on file; only 45% of towns in Quebec do, against 58% across Canada.
NRCan Canada Flood Map Inventory: a study footprint touching the town’s boundary; towns of 2,500 people or more.
The grade leaves flood out, since a study area says nothing about how many of Saint-Ambroise’s homes are at risk.
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-Ambroise: $0.22 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 7.2 times the typical $0.030: Saint-Ambroise’s $0.22 marks real seismic exposure.
Shaking damage a year per $1,000 of building value
Above the middle in Quebec: Saint-Ambroise’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.
Saint-Ambroise is in the top tenth of Canada’s 2,611 towns for earthquake risk; 7.6% rank 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-Ambroise’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).
Radon runs low around Saint-Ambroise: 2.8% of tested homes over the guideline
Health Canada’s survey of long-term home tests: the share above the 200 Bq/m³ guideline. · Measured across the Saguenay - Lac-Saint-Jean health region: radon tests
A lower share than most: 2.8% of tested homes around Saint-Ambroise, the typical Canadian town 6.6%.
Tested homes over 200 Bq/m³
Over 600 Bq/m³
Fewer homes top the guideline around Saint-Ambroise (2.8%) than in the typical town in Quebec (8.2%), yet 1.4% went over 600.
Health Canada radon survey (2009–2011), by 2007 health region; medians of towns of 2,500 people or more.
Under 5% puts Saint-Ambroise with 37% of Canada’s 2,611 towns; 63% have more high tests.
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 share describes the area, not a house: in Saint-Ambroise as anywhere, test to be sure.
Health Canada, Cross-Canada Survey of Radon Concentrations in Homes (2009–2011).
Weather and fire alerts for Saint-Ambroise
Environment and Climate Change Canada issues the weather alerts for Saint-Ambroise; Alert Ready carries the urgent ones to phones, radio and TV.
| 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. |
In fire season, check CWFIS for danger and active fires around Saint-Ambroise, and listen to local authorities for orders.
Weather alerts (ECCC) · Alert Ready · Fire danger and active fires (CWFIS)
Hazards in the places around Saint-Ambroise
The same four hazards for the places next door.
| Town | Wildfire | Quake $/1,000 | Radon | Flood study |
|---|---|---|---|---|
| Saint-Ambroise | Low | $0.22 | 2.8% | None listed |
| Saint-David-de-Falardeau 3,128 · 18 km | Low | $0.16 | 2.8% | None listed |
| Saint-Nazaire 2,167 · 18 km | Low | $0.21 | 2.8% | None listed |
| Labrecque 1,375 · 18 km | Low | $0.18 | 2.8% | None listed |
| Saint-Honoré 6,984 · 18 km | Low | $0.22 | 2.8% | None listed |
| Larouche 1,734 · 19 km | Low | $0.20 | 2.8% | None listed |
The fire record around Larouche is a touch heavier than Saint-Ambroise’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-Ambroise faces
Practical steps for Saint-Ambroise’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?
- Ask the municipality for flood maps.
- 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-Ambroise’s homes since 1986, a history of fire that may lower Risk but never raises it.
- Radon is a survey. The radon share comes from about 14,000 long-term home tests in 2009–2011, pooled for now by the 2007 health region Saint-Ambroise sits in.
- Earthquakes are modelled. NRCan models what earthquakes would cost buildings each year on average, subdivision by subdivision; Saint-Ambroise’s figure is its subdivision’s.
- Flood studies aren’t flood zones. A study’s area can be a whole watershed or province, so being on the inventory says a map exists, not that a home in Saint-Ambroise floods.
Questions about flooding and hazards in Saint-Ambroise
Is radon a problem in Saint-Ambroise?
The area’s survey found 2.8% of 72 tested homes above Health Canada’s guideline, so a three-month test is worth doing in Saint-Ambroise.
How big is the earthquake risk in Saint-Ambroise?
About $0.22 a year per $1,000 of building value, NRCan’s long-run expectation for Saint-Ambroise.
Is Saint-Ambroise at risk of wildfire?
Some, but Saint-Ambroise’s low band (0.3% of nearby land burned since 1986, latest 2023) is short of the level that counts.
How is Saint-Ambroise’s Hazard risk Grade worked out?
Saint-Ambroise’s Hazard risk grade is C+, built on earthquakes and radon with a one-sided wildfire input.
Does Saint-Ambroise flood?
The inventory has 0 studies for Saint-Ambroise, 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).