Photo: Quintin Soloviev · CC BY 4.0Flood mapping exists for Trois-Rivières: 1 on record, latest by Gouvernement du Québec
Burn scars are few around Trois-Rivières, with 0.1% of the land within 25 km touched by fire since 1986 (0.002% a year). Seismic risk runs high: $0.13 of expected damage per $1,000 of buildings a year, the typical town $0.030. Radon is lower than usual: 0% of tested homes in the survey area topped the guideline, against 6.6% for the typical town. Hazard risk gives Trois-Rivières a grade of B+; its wildfire band pulls it down.
What stands out about Trois-Rivières’s hazards
Four national sources, each read for Trois-Rivières: earthquakes, radon, past fires and flood studies.
What Trois-Rivières faces
Each hazard against its own yardstick; meters run from low to high on that yardstick.
Wildfire
Earthquakes
Radon
Flood study
Hazard risk in Trois-Rivières: B+
Two inputs always count for Trois-Rivières, earthquakes and radon; the third, wildfire, counts only against a town.
Its place: #35 of 507 in Quebec and #1,075 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 58 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 Trois-Rivières has burned: 0.3% within 5 km, 0.1% within 25 km since 1986
Fires mapped since 1986 around where Trois-Rivières’ residents live, and the fuel next to their homes.
At 0.002% of the land a year, Trois-Rivières’ burn rate is in the low band; the typical Canadian town sees 0.000%.
The ring nearest Trois-Rivières is the most wooded: 26% forest fuel within 5 km against 21% 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
Mistissini burns fastest in Quebec at 0.31% a year; Trois-Rivières, 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.
7.5% of Canada’s 2,610 towns burn fast enough to rank moderate or above; Trois-Rivières 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.
Gouvernement du Québec has mapped flooding for Trois-Rivières (1 study)
Flood studies whose area touches Trois-Rivières, from NRCan’s inventory, each linked to its owner.
A 1996 study by Gouvernement du Québec covers Trois-Rivières, and its map, not the inventory, shows the zones.
| Study | By | Year | Status |
|---|---|---|---|
| Varennes-Grondines | Gouvernement du Québec | 1996 | final |
Towns with a flood study on file
Only 45% of towns in Quebec have a flood study, short of Canada’s 58%; Trois-Rivières is one of them.
NRCan Canada Flood Map Inventory: a study footprint touching the town’s boundary; towns of 2,500 people or more.
Flood is shown here, never graded: a study says where a map exists, not how many of Trois-Rivières’ homes stand in a flood zone.
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 Trois-Rivières: $0.13 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 $0.13 per $1,000, Trois-Rivières carries roughly 4.2 times the typical Canadian town’s earthquake risk ($0.030).
Shaking damage a year per $1,000 of building value
Typical for its province: Trois-Rivières at $0.13 beside a median in Quebec of $0.14, with La Pocatière on top 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.
More earthquake risk than most: only 22% of Canada’s 2,611 towns are above Trois-Rivières.
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 Trois-Rivières’ 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).
Little radon around Trois-Rivières: 0% 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 Mauricie et Centre-du-Quebec health region
A lower share than most: 0% of tested homes around Trois-Rivières, the typical Canadian town 6.6%.
Tested homes over 200 Bq/m³
Over 600 Bq/m³
Fewer homes top the guideline around Trois-Rivières (0%) than in the typical town in Quebec (8.2%).
Health Canada radon survey (2009–2011), by 2007 health region; medians of towns of 2,500 people or more.
The quietest radon band, under 5%, holds 37% of Canada’s 2,611 towns and Trois-Rivières; 63% sit 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.
Basements, soil and how a house is sealed decide its radon, so in Trois-Rivières only a test can say.
Health Canada, Cross-Canada Survey of Radon Concentrations in Homes (2009–2011).
Weather and fire alerts for Trois-Rivières
Environment and Climate Change Canada issues the weather alerts for Trois-Rivières; 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 Trois-Rivières, and listen to local authorities for orders.
Weather alerts (ECCC) · Alert Ready · Fire danger and active fires (CWFIS)
Hazards in the places around Trois-Rivières
The same four hazards for the places next door.
| Town | Wildfire | Quake $/1,000 | Radon | Flood study |
|---|---|---|---|---|
| Trois-Rivières | Low | $0.13 | 0% | Yes |
| Saint-Maurice 3,804 · 12 km | Low | $0.11 | 0% | None listed |
| Bécancour 14,943 · 12 km | Low | $0.13 | 0% | Yes |
| Nicolet 8,737 · 14 km | Low | $0.12 | 0% | Yes |
| Notre-Dame-du-Mont-Carmel 6,613 · 16 km | Low | $0.098 | 0% | None listed |
| Champlain 1,957 · 17 km | Low | $0.12 | 0% | Yes |
| Saint-Étienne-des-Grès 4,675 · 17 km | Low | $0.11 | 0% | None listed |
Among its neighbours Trois-Rivières has the most fire on record (low); Saint-Maurice follows (low).
Radon is the survey area’s figure, so neighbours in one area share it.
Get ready for what Trois-Rivières faces
What to do about the hazards Trois-Rivières 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
- Wildfire counts one way. The wildfire figure is the share of land within 25 km of Trois-Rivières’ homes burned each year from 1986 to 2025, past fire rather than a forecast, and it can only lower Risk.
- 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 Trois-Rivières’.
- Radon is a survey. About 14,000 homes were tested across Canada in 2009–2011, and the share over the guideline for Trois-Rivières is its health region’s, the survey’s design unit.
- 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 Trois-Rivières.
Questions about flooding and hazards in Trois-Rivières
Does Trois-Rivières flood?
There is flood mapping for Trois-Rivières on the national inventory, each study linked to its owner’s map, none of them graded.
How big is the earthquake risk in Trois-Rivières?
About $0.13 a year per $1,000 of building value, NRCan’s long-run expectation for Trois-Rivières.
Is radon a problem in Trois-Rivières?
In Health Canada’s survey, 0% of 58 homes tested in Trois-Rivières’ area were above 200 Bq/m³, though only a test tells you about one house.
Is Trois-Rivières at risk of wildfire?
Less than most of Canada: 0.1% of the land within 25 km of Trois-Rivières has burned since 1986, the last in 2024, a low band that leaves Risk alone.
How is Trois-Rivières’s Hazard risk Grade worked out?
Trois-Rivières grades B+ for hazard risk, from earthquakes and radon, with wildfire counted only where it lowers 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).