Photo: Gaétan Veillette · CC BY-SA 4.0Flood mapping exists for Saint-Hyacinthe: 1 on record, latest by Gouvernement du Québec
Wildfire isn’t Saint-Hyacinthe’s worry: 0% of the land within 25 km burned since 1986 (0.001% a year). Earthquakes add more: NRCan’s model puts building losses at $0.15 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 Saint-Hyacinthe’s area exceeded 200 Bq/m³, close to the typical 6.6%. Hazard risk gives Saint-Hyacinthe a grade of C, from earthquakes and radon alone.
What stands out about Saint-Hyacinthe’s hazards
For Saint-Hyacinthe, from NRCan’s seismic model, Health Canada’s radon survey, the national burned-area record and the flood map inventory.
What Saint-Hyacinthe faces
Each hazard against its own yardstick; meters run from low to high on that yardstick.
Wildfire
Earthquakes
Radon
Flood study
Saint-Hyacinthe grades C for hazard risk
Two inputs always count for Saint-Hyacinthe, earthquakes and radon; the third, wildfire, counts only against a town.
Its place: #266 of 507 in Quebec and #2,219 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.
Wildfire is rare near Saint-Hyacinthe: 0% of the land within 25 km burned since 1986, 0% within 5 km
Fires mapped since 1986 around where Saint-Hyacinthe’s residents live, and the fuel next to their homes.
Saint-Hyacinthe burns at 0.001% a year, low against 0.000% for the typical Canadian town.
The closest burn since 1986 lies 13 km from Saint-Hyacinthe’s homes, none within 5 km.
Only 2% of the land within 25 km of Saint-Hyacinthe is forest fuel, and 0.4% 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
Saint-Hyacinthe burns at 0.001% a year, 136th of 513 towns in Quebec; the leader, Mistissini, reaches 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.
7.5% of Canada’s 2,610 towns burn fast enough to rank moderate or above; Saint-Hyacinthe 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.
Saint-Hyacinthe is on the flood map inventory: 1 study, by Gouvernement du Québec
Flood studies whose area touches Saint-Hyacinthe, from NRCan’s inventory, each linked to its owner.
The flood study touching Saint-Hyacinthe is Gouvernement du Québec’s, dated 1983; its own map shows the zones street by street.
| Study | By | Year | Status |
|---|---|---|---|
| Yamaska-St-Hyacinthe-St-césaire | Gouvernement du Québec | 1983 | final |
Towns with a flood study on file
Only 45% of towns in Quebec have a flood study, short of Canada’s 58%; Saint-Hyacinthe 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 Saint-Hyacinthe’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.”
Natural Resources Canada, Canada Flood Map Inventory; links go to each study’s owner.
Earthquakes cost buildings in Saint-Hyacinthe $0.15 per $1,000 a year
NRCan’s seismic risk model: the damage shaking is expected to do to buildings each year, on average over many years.
At $0.15 per $1,000, Saint-Hyacinthe carries roughly 5 times the typical Canadian town’s earthquake risk ($0.030).
Shaking damage a year per $1,000 of building value
The median in Quebec is $0.14; Saint-Hyacinthe, at $0.15, 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.
19% of Canada’s 2,611 towns expect more shaking damage than Saint-Hyacinthe, 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).
Only shaking damage to buildings in Saint-Hyacinthe is counted; landslides, liquefaction, tsunami and fire after a quake aren’t.
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 Saint-Hyacinthe are over the radon guideline
Health Canada’s survey of long-term home tests: the share above the 200 Bq/m³ guideline. · Measured across the Monteregie health region: radon tests
Near the middle for radon: Saint-Hyacinthe’s area 8.2%, the typical Canadian town 6.6%.
Tested homes over 200 Bq/m³
Over 600 Bq/m³
Saint-Hyacinthe’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.
26% of Canada’s 2,611 towns have more homes over 200 Bq/m³ than Saint-Hyacinthe’s 5–10% band, which holds 37%.
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.
Radon varies from house to house in Saint-Hyacinthe, so the survey is a reason to test, not a result for yours.
Health Canada, Cross-Canada Survey of Radon Concentrations in Homes (2009–2011).
Where to get warnings in Saint-Hyacinthe
Environment and Climate Change Canada issues the weather alerts for Saint-Hyacinthe; 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 Saint-Hyacinthe, and listen to local authorities for orders.
Weather alerts (ECCC) · Alert Ready · Fire danger and active fires (CWFIS)
How Saint-Hyacinthe’s neighbours compare on hazards
The same four hazards for the places next door.
| Town | Wildfire | Quake $/1,000 | Radon | Flood study |
|---|---|---|---|---|
| Saint-Hyacinthe | Low | $0.15 | 8.2% | Yes |
| La Présentation 2,696 · 7.7 km | Low | $0.15 | 8.2% | None listed |
| Saint-Barnabé-Sud 1,053 · 10 km | Low | $0.15 | 8.2% | Yes |
| Saint-Dominique 3,062 · 10 km | Low | $0.11 | 8.2% | None listed |
| Sainte-Madeleine 2,387 · 12 km | Low | $0.16 | 8.2% | None listed |
| Sainte-Marie-Madeleine 2,940 · 12 km | Low | $0.16 | 8.2% | Yes |
| Saint-Simon 1,474 · 12 km | Low | $0.12 | 8.2% | Yes |
Among its neighbours Saint-Hyacinthe has the most fire on record (low); La Présentation follows (low).
Radon is the survey area’s figure, so neighbours in one area share it.
Get ready for what Saint-Hyacinthe faces
What to do about the hazards Saint-Hyacinthe 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
- Earthquakes are modelled. The earthquake figure is an expected loss, not a forecast, worked out by NRCan for each census subdivision, Saint-Hyacinthe’s included.
- 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 Saint-Hyacinthe.
- Radon is a survey. About 14,000 homes were tested across Canada in 2009–2011, and the share over the guideline for Saint-Hyacinthe 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 Saint-Hyacinthe.
Questions about flooding and hazards in Saint-Hyacinthe
How big is the earthquake risk in Saint-Hyacinthe?
About $0.15 a year per $1,000 of building value, NRCan’s long-run expectation for Saint-Hyacinthe.
Is Saint-Hyacinthe at risk of wildfire?
Less than most of Canada: 0% of the land within 25 km of Saint-Hyacinthe has burned since 1986, the last in 2025, a low band that leaves Risk alone.
Does Saint-Hyacinthe flood?
There is flood mapping for Saint-Hyacinthe on the national inventory, each study linked to its owner’s map, none of them graded.
Is radon a problem in Saint-Hyacinthe?
In Health Canada’s survey, 8.2% of 110 homes tested in Saint-Hyacinthe’s area were above 200 Bq/m³, though only a test tells you about one house.
How is Saint-Hyacinthe’s Hazard risk Grade worked out?
Saint-Hyacinthe’s Hazard risk grade is C, built on earthquakes and radon with a one-sided wildfire input.
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).