Photo: P199 · CC BY-SA 4.0Flood mapping exists for Saint-Chrysostome: 1 on record, latest by MRC du Haut Saint Laurent
Fire has left almost no mark near Saint-Chrysostome: 0% of the land within 25 km since 1986, 0.001% a year. Seismic risk runs high: $0.20 of expected damage per $1,000 of buildings a year, the typical town $0.030. In Health Canada’s survey, 8.2% of homes tested in Saint-Chrysostome’s area exceeded 200 Bq/m³, close to the typical 6.6%. Hazard risk gives Saint-Chrysostome a grade of C−, from earthquakes and radon alone.
What stands out about Saint-Chrysostome’s hazards
Four national sources, each read for Saint-Chrysostome: earthquakes, radon, past fires and flood studies.
What Saint-Chrysostome faces
Each hazard against its own yardstick; meters run from low to high on that yardstick.
Wildfire
Earthquakes
Radon
Flood study
Hazard risk in Saint-Chrysostome: C−
For Saint-Chrysostome, Risk will be the average of earthquakes and radon, with wildfire added only if it makes the average worse.
Its place: #362 of 507 in Quebec and #2,333 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 Saint-Chrysostome: 0% within 5 km, 0% within 25 km
Fires mapped since 1986 around where Saint-Chrysostome’s residents live, and the fuel next to their homes.
In a typical year 0.001% of the land near Saint-Chrysostome burns; the typical Canadian town sees 0.000%, and both are low.
Nothing inside 5 km of Saint-Chrysostome’s homes has burned since 1986, and the nearest scar is 8.6 km off.
Close to Saint-Chrysostome there is little to burn (4.5% forest fuel within 5 km), but 5.9% of the land within 25 km is forest.
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-Chrysostome 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-Chrysostome 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.
A flood study covers Saint-Chrysostome, from MRC du Haut Saint Laurent: 1 on the inventory
Flood studies whose area touches Saint-Chrysostome, from NRCan’s inventory, each linked to its owner.
MRC du Haut Saint Laurent studied flooding in an area that includes Saint-Chrysostome (2016); open its map to see which streets lie in a flood zone.
| Study | By | Year | Status |
|---|---|---|---|
| St-Chrysostome-Très-St-Sacrement | MRC du Haut Saint Laurent | 2016 | final |
Towns with a flood study on file
Only 45% of towns in Quebec have a flood study, short of Canada’s 58%; Saint-Chrysostome is one of them.
NRCan Canada Flood Map Inventory: a study footprint touching the town’s boundary; towns of 2,500 people or more.
Listed, not scored: a flood study proves a map exists, not that Saint-Chrysostome 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 Saint-Chrysostome: $0.20 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.
Saint-Chrysostome’s $0.20 is about 6.5 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
The typical town in Quebec expects $0.14 a year; Saint-Chrysostome expects $0.20, and La Pocatière $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 Saint-Chrysostome, 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).
The loss is to Saint-Chrysostome’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).
8.2% of homes tested around Saint-Chrysostome are over the radon guideline
Health Canada’s survey of long-term home tests: the share above the 200 Bq/m³ guideline.
Near the middle for radon: Saint-Chrysostome’s area 8.2%, the typical Canadian town 6.6%. For radon tests, the only official count covers all of the Monteregie health region, Saint-Chrysostome included.
Tested homes over 200 Bq/m³
Over 600 Bq/m³
The typical town in Quebec has 8.2% over 200 Bq/m³; Saint-Chrysostome’s area has 8.2%, much the same.
Health Canada radon survey (2009–2011), by 2007 health region; medians of towns of 2,500 people or more.
Between 5% and 10% of tests over the guideline: Saint-Chrysostome, and 37% of Canada’s 2,611 towns; 26% are 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.
A survey sample isn’t a map: any home in Saint-Chrysostome can be high, and a three-month test is the only way to know.
Health Canada, Cross-Canada Survey of Radon Concentrations in Homes (2009–2011).
Weather and fire alerts for Saint-Chrysostome
Alerts for Saint-Chrysostome 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. |
Fire danger and active fires near Saint-Chrysostome are mapped daily by the Canadian Wildland Fire Information System; evacuation orders come from the municipality or province.
Weather alerts (ECCC) · Alert Ready · Fire danger and active fires (CWFIS)
Hazards in the places around Saint-Chrysostome
The same four hazards for the places next door.
| Town | Wildfire | Quake $/1,000 | Radon | Flood study |
|---|---|---|---|---|
| Saint-Chrysostome | Low | $0.20 | 8.2% | Yes |
| Sainte-Clotilde 3,297 · 6.7 km | Low | $0.20 | 8.2% | None listed |
| Hemmingford 2,206 · 11 km | Low | $0.18 | 8.2% | None listed |
| Très-Saint-Sacrement 1,223 · 13 km | Low | $0.20 | 8.2% | Yes |
| Saint-Urbain-Premier 1,380 · 14 km | Low | $0.19 | 8.2% | None listed |
| Franklin 1,754 · 14 km | Low | $0.16 | 8.2% | None listed |
| Sainte-Martine 5,884 · 17 km | Low | $0.19 | 8.2% | Yes |
Très-Saint-Sacrement burns a little more than Saint-Chrysostome, 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 Saint-Chrysostome faces
Practical steps for Saint-Chrysostome’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
- 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 Saint-Chrysostome floods.
- Wildfire counts one way. The wildfire figure is the share of land within 25 km of Saint-Chrysostome’s 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 Saint-Chrysostome’s.
- 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 Saint-Chrysostome sits in.
Questions about flooding and hazards in Saint-Chrysostome
How is Saint-Chrysostome’s Hazard risk Grade worked out?
Saint-Chrysostome’s Hazard risk grade is C−, built on earthquakes and radon with a one-sided wildfire input.
Is Saint-Chrysostome at risk of wildfire?
Not much by Canadian standards: Saint-Chrysostome’s band is low, with 0% of the land within 25 km burned since 1986 (last in 2015), so wildfire doesn’t change its grade.
How big is the earthquake risk in Saint-Chrysostome?
Expected earthquake damage in Saint-Chrysostome comes to $0.20 a year for each $1,000 that buildings are worth.
Does Saint-Chrysostome flood?
Saint-Chrysostome’s area has been studied for flooding, and the owner’s map shows which streets lie in a zone; the grade leaves flood out.
Is radon a problem in Saint-Chrysostome?
8.2% of the 110 homes Health Canada tested around Saint-Chrysostome topped the guideline; your own house needs its own test.
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).