Photo: Fralambert · CC BY-SA 4.0Yamaska is on Canada’s flood inventory: 2 listed, led by Gouvernement du Québec
For Yamaska, wildfire history is close to nil: 0% of nearby land since 1986, 0.001% 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). Radon around Yamaska is ordinary for Canada: 8.2% of tested homes over the guideline (6.6% typical). Yamaska grades C for hazard risk; wildfire is low here, so it earns no credit.
What stands out about Yamaska’s hazards
For Yamaska, from NRCan’s seismic model, Health Canada’s radon survey, the national burned-area record and the flood map inventory.
What Yamaska faces
Each hazard against its own yardstick; meters run from low to high on that yardstick.
Wildfire
Earthquakes
Radon
Flood study
Hazard risk in Yamaska: C
Earthquake risk and radon make Yamaska’s grade; wildfire can only lower it, never raise it, and flood studies are listed but not scored.
How sure: The seismic figure is a long-run average from NRCan’s model, not a prediction. The burned-area record misses fires under about 10 ha and most grass and farm fires.
Little of the land around Yamaska has burned: 0% within 5 km, 0% within 25 km since 1986
Past fire around Yamaska’s homes, from the national burned-area record, with the fuel within 5 km.
The land within 25 km of Yamaska burns at 0.001% a year on average, the low band; the typical Canadian town: 0.000%.
The 5 km ring around Yamaska’s homes is clear of burns since 1986, the nearest 12 km out.
The forest starts beyond town: 2.9% of the land within 5 km of Yamaska’s homes is forest fuel, against 5.5% 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 514
In the upper half in Quebec but far from Mistissini (0.31%): Yamaska ranks 136th of 514, at 0.001% a year.
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.
Low, like 92% of the country’s 2,610 towns: the land around Yamaska burns, but slower than in the 7.5% above it.
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.
Yamaska is on the flood map inventory: 2 studies, latest by Gouvernement du Québec
What Canada’s Flood Map Inventory lists for Yamaska: who studied flooding and where to see their maps.
2 studies on the inventory touch Yamaska, the newest Gouvernement du Québec’s from 1996, and their areas can be large, so they say maps exist, not that the town floods.
| Study | By | Year | Status |
|---|---|---|---|
| Varennes-Grondines | Gouvernement du Québec | 1996 | final |
| Yamaska-St-Hyacinthe-St-césaire | Gouvernement du Québec | 1983 | final |
Towns with a flood study on file
Yamaska 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.
No single decade dominates: 2 studies for Yamaska between the 1980s and the 1990s.
Study dates as the NRCan inventory lists them, one count per study touching Yamaska.
Flood mapping is shown for Yamaska 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.
High seismic risk in Yamaska: $0.14 per $1,000 of buildings a year
Expected yearly building losses from earthquakes, from Natural Resources Canada’s model.
Yamaska’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
Neither high nor low in Quebec: Yamaska’s $0.14 sits by the median of $0.14, while La Pocatière reaches $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.
In the upper part of Canada’s range: 22% of its 2,611 towns expect more damage than Yamaska.
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).
For Yamaska the model prices shaking damage to buildings, nothing more.
Natural Resources Canada, Canada’s Seismic Risk Model (2022), by census subdivision (2016 boundaries; a few 2021 subdivisions take their residents’ mean).
8.2% of homes tested around Yamaska are over the radon guideline
Long-term radon tests in homes across the survey area, against Health Canada’s guideline.
8.2% of tested homes around Yamaska were over the guideline, much like the typical Canadian town at 6.6%. Figures for radon tests are published for the Monteregie health region as a whole, not for Yamaska alone.
Tested homes over 200 Bq/m³
Over 600 Bq/m³
Radon around Yamaska 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.
37% of Canada’s 2,611 towns share Yamaska’s band of 5 to 10%; 26% 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.
Whatever Yamaska’s area share, the reading that matters is your own home’s, over a winter.
Health Canada, Cross-Canada Survey of Radon Concentrations in Homes (2009–2011).
Where to get warnings in Yamaska
Alerts for Yamaska 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 Yamaska 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 Yamaska
Wildfire band, earthquake risk, radon and flood studies for each place nearby.
| Town | Wildfire | Quake $/1,000 | Radon | Flood study |
|---|---|---|---|---|
| Yamaska | Low | $0.14 | 8.2% | Yes |
| Saint-Robert 1,846 · 4.7 km | Low | $0.15 | 8.2% | Yes |
| Saint-François-du-Lac 1,927 · 9.8 km | Low | $0.12 | 0% | Yes |
| Sainte-Anne-de-Sorel 2,770 · 11 km | Low | $0.12 | 8.2% | Yes |
| Pierreville 2,154 · 11 km | Low | $0.14 | 0% | Yes |
| Sainte-Victoire-de-Sorel 2,599 · 14 km | Low | $0.13 | 8.2% | Yes |
| Sorel-Tracy 36,537 · 16 km | Low | $0.15 | 8.2% | Yes |
Saint-Robert (low) has the heaviest fire record of Yamaska’s neighbours, and Yamaska (low) matches or beats it.
Radon is the survey area’s figure, so neighbours in one area share it.
Get ready for what Yamaska faces
Practical steps for Yamaska’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
- Wildfire counts one way. Burned land within 25 km of where people live, averaged over 1986–2025 and checked for fuel near homes, is the measure; it looks back, not ahead, and only ever counts against Yamaska.
- 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 Yamaska floods.
- 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 Yamaska sits in.
- Earthquakes are modelled. The earthquake figure is an expected loss, not a forecast, worked out by NRCan for each census subdivision, Yamaska’s included.
Questions about flooding and hazards in Yamaska
How is Yamaska’s Hazard risk Grade worked out?
Yamaska grades C for hazard risk, from earthquakes and radon, with wildfire counted only where it lowers the grade.
Is Yamaska at risk of wildfire?
Not much by Canadian standards: Yamaska’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.
Is radon a problem in Yamaska?
8.2% of the 110 homes Health Canada tested around Yamaska topped the guideline; your own house needs its own test.
How big is the earthquake risk in Yamaska?
NRCan’s model expects shaking to cost buildings in Yamaska $0.14 a year for every $1,000 of their value, on average over many years.
Does Yamaska flood?
Yamaska’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).