Photo: Pierre Bona · CC BY-SA 3.0Wildfire low, radon 8.2%: how Mont-Saint-Grégoire stands on hazards
Little of the land around Mont-Saint-Grégoire has burned: 0% within 25 km since 1986, or 0.001% a year. Earthquakes add more: NRCan’s model puts building losses at $0.16 a year per $1,000 of value, against $0.030 for the typical town. Mont-Saint-Grégoire grades C for hazard risk; wildfire is low here, so it earns no credit.
What stands out about Mont-Saint-Grégoire’s hazards
Four national sources, each read for Mont-Saint-Grégoire: earthquakes, radon, past fires and flood studies.
What Mont-Saint-Grégoire faces
Each hazard against its own yardstick; meters run from low to high on that yardstick.
Wildfire
Earthquakes
Radon
Flood study
Hazard risk in Mont-Saint-Grégoire: C
The grade weighs Mont-Saint-Grégoire’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: #286 of 507 in Quebec and #2,243 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.
Few fires near Mont-Saint-Grégoire: 0% within 5 km, 0% within 25 km
Past fire around Mont-Saint-Grégoire’s homes, from the national burned-area record, with the fuel within 5 km.
Low: the land around Mont-Saint-Grégoire burns at 0.001% a year, where the typical Canadian town sees 0.000%.
Little near Mont-Saint-Grégoire’s homes can carry a forest fire; only 0.1% of the land within 5 km is forest fuel, and 1% 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
At 0.001% a year, Mont-Saint-Grégoire ranks 136th of the 513 towns in Quebec; 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.
Beside 2,610 Canadian towns, Mont-Saint-Grégoire reads low, with 92% of them; only 7.5% rank 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.
The flood map inventory lists nothing for Mont-Saint-Grégoire
What Canada’s Flood Map Inventory lists for Mont-Saint-Grégoire: who studied flooding and where to see their maps.
Canada’s Flood Map Inventory lists no study whose area touches Mont-Saint-Grégoire, which doesn’t mean it has never been mapped.
Towns with a flood study on file
Flood maps are thinner in Quebec, 45% of towns against 58% nationally, and Mont-Saint-Grégoire has none.
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 Mont-Saint-Grégoire’s 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.”
High seismic risk in Mont-Saint-Grégoire: $0.16 per $1,000 of buildings a year
Expected yearly building losses from earthquakes, from Natural Resources Canada’s model.
At $0.16 per $1,000, Mont-Saint-Grégoire carries roughly 5.4 times the typical Canadian town’s earthquake risk ($0.030).
Shaking damage a year per $1,000 of building value
Shaking damage around Mont-Saint-Grégoire runs at $0.16 a year, near the $0.14 of the typical town in Quebec; La Pocatière has $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 14% of Canada’s 2,611 towns are above Mont-Saint-Grégoire.
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 loss is to Mont-Saint-Grégoire’s buildings alone, from ground shaking; infrastructure and secondary hazards are left out.
Natural Resources Canada, Canada’s Seismic Risk Model (2022), by census subdivision (2016 boundaries; a few 2021 subdivisions take their residents’ mean).
Radon about average around Mont-Saint-Grégoire: 8.2% over the guideline
Long-term radon tests in homes across the survey area, against Health Canada’s guideline.
At 8.2% over the guideline, the area around Mont-Saint-Grégoire is about level with the typical Canadian town’s 6.6%.
Tested homes over 200 Bq/m³
Over 600 Bq/m³
Radon around Mont-Saint-Grégoire is ordinary for towns in Quebec: 8.2%, beside a median of 8.2%.
Health Canada radon survey (2009–2011), by 2007 health region; medians of towns of 2,500 people or more.
Mont-Saint-Grégoire is in the 5–10% band with 37% of Canada’s 2,611 towns; 26% have more.
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 Mont-Saint-Grégoire; it can’t tell you your basement’s level.
Health Canada, Cross-Canada Survey of Radon Concentrations in Homes (2009–2011). · Radon tests published for the Monteregie health region, not by town
Weather and fire alerts for Mont-Saint-Grégoire
Environment and Climate Change Canada issues the weather alerts for Mont-Saint-Grégoire; 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. |
For fires near Mont-Saint-Grégoire, the national fire information system maps danger and active fires daily; local authorities give any evacuation order.
Weather alerts (ECCC) · Alert Ready · Fire danger and active fires (CWFIS)
How Mont-Saint-Grégoire’s neighbours compare on hazards
Wildfire band, earthquake risk, radon and flood studies for each place nearby.
| Town | Wildfire | Quake $/1,000 | Radon | Flood study |
|---|---|---|---|---|
| Mont-Saint-Grégoire | Low | $0.16 | 8.2% | None listed |
| Sainte-Brigide-d'Iberville 1,540 · 7.9 km | Low | $0.15 | 8.2% | Yes |
| Sainte-Angèle-de-Monnoir 1,862 · 8.4 km | Low | $0.14 | 8.2% | None listed |
| Saint-Jean-sur-Richelieu 100,806 · 9.0 km | Low | $0.19 | 8.2% | Yes |
| Marieville 11,910 · 10 km | Low | $0.16 | 8.2% | None listed |
| Richelieu 6,048 · 12 km | Low | $0.18 | 8.2% | Yes |
| Saint-Alexandre 2,685 · 12 km | Low | $0.16 | 8.2% | None listed |
Richelieu burns a little more than Mont-Saint-Grégoire, in the same low band (low here).
Radon is the survey area’s figure, so neighbours in one area share it.
Get ready for what Mont-Saint-Grégoire faces
What to do about the hazards Mont-Saint-Grégoire 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?
- 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. Shaking damage is modelled from the ground, the buildings and the odds of each quake, and published for whole subdivisions such as Mont-Saint-Grégoire’s.
- Flood studies aren’t flood zones. Flood studies cover areas of every size, which is why the page lists them for Mont-Saint-Grégoire without grading them.
- Wildfire counts one way. The wildfire figure is the share of land within 25 km of Mont-Saint-Grégoire’s homes burned each year from 1986 to 2025, past fire rather than a forecast, and it can only lower Risk.
- Radon is a survey. Radon figures pool the survey’s home tests by area: postal areas once their boundaries arrive, the 2007 health region around Mont-Saint-Grégoire until then.
Questions about flooding and hazards in Mont-Saint-Grégoire
Is Mont-Saint-Grégoire at risk of wildfire?
Less than most of Canada: 0% of the land within 25 km of Mont-Saint-Grégoire has burned since 1986, the last in 2025, a low band that leaves Risk alone.
Does Mont-Saint-Grégoire flood?
Nothing is listed for Mont-Saint-Grégoire on the national inventory (0); local maps may still exist with the municipality.
Is radon a problem in Mont-Saint-Grégoire?
In Health Canada’s survey, 8.2% of 110 homes tested in Mont-Saint-Grégoire’s area were above 200 Bq/m³, though only a test tells you about one house.
How is Mont-Saint-Grégoire’s Hazard risk Grade worked out?
Mont-Saint-Grégoire’s Hazard risk grade is C, built on earthquakes and radon with a one-sided wildfire input.
How big is the earthquake risk in Mont-Saint-Grégoire?
NRCan’s model expects shaking to cost buildings in Mont-Saint-Grégoire $0.16 a year for every $1,000 of their value, on average over many years.
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).