Photo: Minoumi · Public domainFlood mapping exists for Chambly: 2 on record, latest by Gouvernement du Québec
Burn scars are few around Chambly, with 0.1% of the land within 25 km touched by fire since 1986 (0.002% a year). Earthquakes add more: NRCan’s model puts building losses at $0.19 a year per $1,000 of value, against $0.030 for the typical town. In Health Canada’s survey, 8.2% of homes tested in Chambly’s area exceeded 200 Bq/m³, close to the typical 6.6%. Hazard risk gives Chambly a grade of C−, from earthquakes and radon alone.
What stands out about Chambly’s hazards
For Chambly, from NRCan’s seismic model, Health Canada’s radon survey, the national burned-area record and the flood map inventory.
What Chambly faces
Each hazard against its own yardstick; meters run from low to high on that yardstick.
Wildfire
Earthquakes
Radon
Flood study
Hazard risk in Chambly: C−
The grade weighs Chambly’s seismic risk and radon equally, and wildfire is one-sided: a high band counts against a town, a low one earns nothing.
Its place: #359 of 507 in Quebec and #2,330 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 Chambly: 0% within 5 km, 0.1% within 25 km
Fires mapped since 1986 around where Chambly’s residents live, and the fuel next to their homes.
Next to the typical Canadian town (0.000% a year), Chambly’s 0.002% is in the low band.
Nothing inside 5 km of Chambly’s homes has burned since 1986, and the nearest scar is 5.3 km off.
Only 0.5% of the land within 25 km of Chambly is forest fuel, and 0.2% close in.
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
Mistissini burns fastest in Quebec at 0.31% a year; Chambly, at 0.002%, ranks 35th of 513.
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.
Chambly is in the low band with 92% of Canada’s 2,610 towns; 7.5% sit in moderate or 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.
2 flood studies cover Chambly, the newest from Gouvernement du Québec
Flood studies whose area touches Chambly, from NRCan’s inventory, each linked to its owner.
The newest of 2 studies covering Chambly is Gouvernement du Québec’s, from 2005; open its map to see the zones.
| Study | By | Year | Status |
|---|---|---|---|
| Carignan | Gouvernement du Québec | 2005 | final |
| Sorel-Chambly | Gouvernement du Québec | 1979 | final |
Towns with a flood study on file
Flood maps are thinner in Quebec, 45% of towns against 58% nationally, but Chambly has one.
NRCan Canada Flood Map Inventory: a study footprint touching the town’s boundary; towns of 2,500 people or more.
The 2 studies touching Chambly are spread over time, from the 1970s to the 2000s.
Study dates as the NRCan inventory lists them, one count per study touching Chambly.
Listed, not scored: a flood study proves a map exists, not that Chambly 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.
High seismic risk in Chambly: $0.19 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.
At $0.19 per $1,000, Chambly carries roughly 6.4 times the typical Canadian town’s earthquake risk ($0.030).
Shaking damage a year per $1,000 of building value
At $0.19, Chambly 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.
12% of Canada’s 2,611 towns expect more shaking damage than Chambly, 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).
What a quake does after the shaking, fire, landslides, tsunami, falls outside NRCan’s figure for Chambly.
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 Chambly: 8.2% of area homes over the guideline
Health Canada’s survey of long-term home tests: the share above the 200 Bq/m³ guideline. · Source area for radon tests: the Monteregie health region
The survey area of Chambly reads 8.2%, a shade from the typical Canadian town’s 6.6%.
Tested homes over 200 Bq/m³
Over 600 Bq/m³
Chambly’s area, at 8.2%, is close to 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.
A middling share of high tests puts Chambly with 37% of Canada’s 2,611 towns, below 26% of them.
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.
Neighbouring homes in Chambly can differ a lot; only a long-term test tells you about yours.
Health Canada, Cross-Canada Survey of Radon Concentrations in Homes (2009–2011).
Where to get warnings in Chambly
Alerts for Chambly 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 Chambly 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)
How Chambly’s neighbours compare on hazards
The same four hazards for the places next door.
| Town | Wildfire | Quake $/1,000 | Radon | Flood study |
|---|---|---|---|---|
| Chambly | Low | $0.19 | 8.2% | Yes |
| Carignan 12,618 · 2.6 km | Low | $0.18 | 8.2% | Yes |
| Richelieu 6,048 · 4.3 km | Low | $0.18 | 8.2% | Yes |
| Saint-Mathias-sur-Richelieu 4,598 · 5.5 km | Low | $0.18 | 8.2% | Yes |
| Bienville 7,888 · 7.1 km | Low | $0.23 | 8.2% | None listed |
| Saint-Basile-le-Grand 17,146 · 9.3 km | Low | $0.18 | 8.2% | Yes |
| Marieville 11,910 · 10 km | Low | $0.16 | 8.2% | None listed |
Fire is no heavier anywhere nearby than around Chambly (low), with Carignan next at low.
Radon is the survey area’s figure, so neighbours in one area share it.
Get ready for what Chambly faces
What to do about the hazards Chambly faces, and what to ask before you buy.
- 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
- Radon is a survey. Health Canada’s survey tested some 14,000 homes over three months; until postal-area boundaries are loaded, Chambly takes its 2007 health region’s share.
- Wildfire counts one way. For Chambly, wildfire means how much nearby land burned in the past forty years, a one-way input that can pull Risk down and nothing more.
- 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 Chambly.
- Earthquakes are modelled. Seismic risk is NRCan’s model of yearly building losses from shaking, averaged over many years and given for Chambly’s census subdivision (a neighbourhood shows its city’s).
Questions about flooding and hazards in Chambly
Is radon a problem in Chambly?
In Health Canada’s survey, 8.2% of 110 homes tested in Chambly’s area were above 200 Bq/m³, though only a test tells you about one house.
How big is the earthquake risk in Chambly?
Expected earthquake damage in Chambly comes to $0.19 a year for each $1,000 that buildings are worth.
How is Chambly’s Hazard risk Grade worked out?
Chambly grades C− for hazard risk, from earthquakes and radon, with wildfire counted only where it lowers the grade.
Is Chambly at risk of wildfire?
Less than most of Canada: 0.1% of the land within 25 km of Chambly has burned since 1986, the last in 2024, a low band that leaves Risk alone.
Does Chambly flood?
The inventory lists a study touching Chambly; whether a given street floods is on that map, not in the grade.
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).