Photo: Bernard Gagnon · CC BY-SA 3.0On hazards, Saint-Henri comes out behind 92% of Canadian towns
Burn scars are few around Saint-Henri, with 0% of the land within 25 km touched by fire since 1986 (0.000% a year). Shaking is a bigger worry than in most places, at $0.14 a year per $1,000 of building value ($0.030 typical). In Health Canada’s survey, 13% of homes tested in the area exceeded 200 Bq/m³ (6.6% typical). Saint-Henri grades D for hazard risk; wildfire is low here, so it earns no credit.
What stands out about Saint-Henri’s hazards
Four national sources, each read for Saint-Henri: earthquakes, radon, past fires and flood studies.
What Saint-Henri 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-Henri: D
Earthquake risk and radon make Saint-Henri’s grade; wildfire can only lower it, never raise it, and flood studies are listed but not scored.
Its place: #479 of 507 in Quebec and #2,489 of 2,589 Canadian towns.
How sure: The seismic figure is a long-run average from NRCan’s model, not a prediction. Small fires and grass fires are largely missing from the national burned-area record.
Wildfire is rare near Saint-Henri: 0% of the land within 25 km burned since 1986, 0% within 5 km
Past fire around Saint-Henri’s homes, from the national burned-area record, with the fuel within 5 km.
Fire claims 0.000% of the land around Saint-Henri each year, a low band, with the typical Canadian town at 0.000%.
There is forest near Saint-Henri’s homes (13% within 5 km) and more of it further out (19% 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
Little or nothing burns around Saint-Henri in a typical year; 144 of the 513 towns in Quebec share that, and Mistissini leads 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.
92% of Canada’s 2,610 towns are in the low band and 7.5% above it; Saint-Henri 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.
2 flood studies cover Saint-Henri, the newest from Gouvernement du Québec
What Canada’s Flood Map Inventory lists for Saint-Henri: who studied flooding and where to see their maps.
The newest of 2 studies covering Saint-Henri is Gouvernement du Québec’s, from 2012; open its map to see the zones.
| Study | By | Year | Status |
|---|---|---|---|
| St-Anselme | Gouvernement du Québec | 2012 | final |
| Lévis-St-Henri | Gouvernement du Québec | 2005 | final |
Towns with a flood study on file
Saint-Henri 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.
Flood mapping around Saint-Henri has come in steps: 2 studies from the 2000s to the 2010s.
Study dates as the NRCan inventory lists them, one count per study touching Saint-Henri.
Flood mapping is shown for Saint-Henri to be opened and checked, never turned into a grade.
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-Henri’s costliest hazard: $0.14 a year per $1,000
Expected yearly building losses from earthquakes, from Natural Resources Canada’s model.
Saint-Henri’s $0.14 is about 4.6 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
The median in Quebec is $0.14; Saint-Henri, at $0.14, is right beside it, and La Pocatière tops the list 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.
20% of Canada’s 2,611 towns expect more shaking damage than Saint-Henri, which places it in the upper third.
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-Henri’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 high around Saint-Henri: 13% of tested homes over the guideline
Long-term radon tests in homes across the survey area, against Health Canada’s guideline.
Radon runs above the typical Canadian town (6.6%) in Saint-Henri’s area, at 13%. Saint-Henri doesn’t get its own radon tests figures; the ones here come from the Chaudiere-Appalaches health region.
Tested homes over 200 Bq/m³
Over 600 Bq/m³
Saint-Henri’s area, at 13%, is above the median in Quebec (8.2%), and 0.6% of its tests passed 600 Bq/m³.
Health Canada radon survey (2009–2011), by 2007 health region; medians of towns of 2,500 people or more.
One test in ten or more tops the guideline around Saint-Henri, as in 22% of Canada’s 2,611 towns; 4.6% go 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.
The survey sampled homes around Saint-Henri; it can’t tell you your basement’s level.
Health Canada, Cross-Canada Survey of Radon Concentrations in Homes (2009–2011).
Weather and fire alerts for Saint-Henri
Alerts for Saint-Henri 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. |
Evacuation orders for Saint-Henri come from the municipality or the province, while CWFIS maps fire danger every day.
Weather alerts (ECCC) · Alert Ready · Fire danger and active fires (CWFIS)
Hazards in the places around Saint-Henri
Wildfire band, earthquake risk, radon and flood studies for each place nearby.
| Town | Wildfire | Quake $/1,000 | Radon | Flood study |
|---|---|---|---|---|
| Saint-Henri | Low | $0.14 | 13% | Yes |
| Saint-Anselme 4,534 · 11 km | Low | $0.13 | 13% | Yes |
| Saint-Charles-de-Bellechasse 2,739 · 13 km | Low | $0.13 | 13% | None listed |
| Lévis 160,882 · 13 km | Low | $0.15 | 13% | Yes |
| Saint-Gervais 2,235 · 14 km | Low | $0.090 | 13% | None listed |
| Saint-Isidore 3,550 · 14 km | Low | $0.12 | 13% | None listed |
| Beaumont 3,188 · 15 km | Low | $0.15 | 13% | None listed |
The neighbour with the most fire is Saint-Anselme (low), still no more than Saint-Henri (low).
Radon is the survey area’s figure, so neighbours in one area share it.
Get ready for what Saint-Henri faces
Practical steps for Saint-Henri’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. 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-Henri floods.
- Wildfire counts one way. Wildfire is read from the national burned-area record around Saint-Henri’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-Henri sits in.
- Earthquakes are modelled. NRCan models what earthquakes would cost buildings each year on average, subdivision by subdivision; Saint-Henri’s figure is its subdivision’s.
Questions about flooding and hazards in Saint-Henri
Is radon a problem in Saint-Henri?
13% of the 175 homes Health Canada tested around Saint-Henri topped the guideline; your own house needs its own test.
How is Saint-Henri’s Hazard risk Grade worked out?
Saint-Henri’s Hazard risk grade is D, built on earthquakes and radon with a one-sided wildfire input.
How big is the earthquake risk in Saint-Henri?
In NRCan’s seismic model, Saint-Henri’s buildings lose $0.14 per $1,000 of value in an average year.
Is Saint-Henri at risk of wildfire?
Not much by Canadian standards: Saint-Henri’s band is low, with 0% of the land within 25 km burned since 1986 (last in 2022), so wildfire doesn’t change its grade.
Does Saint-Henri flood?
Saint-Henri’s area has been studied for flooding, and the owner’s map shows which streets lie in a zone; the grade leaves flood out.
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).