![Rue principale à l' Assomption . - [1930]](https://images.townratings.com/ca/town_images/52460028/def0e20b8d429e5ffd41.jpg)
Photo: Unknown Unknown · Public domainFlood mapping exists for L'Assomption: 2 on record, latest by Gouvernement du Québec
Little of the land around L'Assomption has burned: 0.1% within 25 km since 1986, or 0.001% a year. Shaking is a bigger worry than in most places, at $0.18 a year per $1,000 of building value ($0.030 typical). Radon is lower than usual: 3.9% of tested homes in the survey area topped the guideline, against 6.6% for the typical town. L'Assomption grades C+ for hazard risk; wildfire is low here, so it earns no credit.
What stands out about L'Assomption’s hazards
For L'Assomption, from NRCan’s seismic model, Health Canada’s radon survey, the national burned-area record and the flood map inventory.
What L'Assomption faces
Each hazard against its own yardstick; meters run from low to high on that yardstick.
Wildfire
Earthquakes
Radon
Flood study
Hazard risk in L'Assomption: C+
Two inputs always count for L'Assomption, earthquakes and radon; the third, wildfire, counts only against a town.
Its place: #104 of 507 in Quebec and #1,782 of 2,589 Canadian towns.
How sure: The seismic figure is a long-run average from NRCan’s model, not a prediction. Only 77 homes were tested in the survey area, so the radon share is rough. The burned-area record misses fires under about 10 ha and most grass and farm fires.
Little of the land around L'Assomption has burned: 0.1% within 5 km, 0.1% within 25 km since 1986
Past fire around L'Assomption’s homes, from the national burned-area record, with the fuel within 5 km.
Around L'Assomption fire takes 0.001% of the land in a typical year, the typical Canadian town 0.000%, which is low.
Little near L'Assomption’s homes can carry a forest fire; only 4.2% of the land within 5 km is forest fuel, and 4.7% 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, L'Assomption 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.
Low, like 92% of the country’s 2,610 towns: the land around L'Assomption 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.
Flooding around L'Assomption is mapped in 2 studies, the newest by Gouvernement du Québec
What Canada’s Flood Map Inventory lists for L'Assomption: who studied flooding and where to see their maps.
2 studies on the inventory touch L'Assomption, the newest Gouvernement du Québec’s from 2006, and their areas can be large, so they say maps exist, not that the town floods.
| Study | By | Year | Status |
|---|---|---|---|
| Assomption | Gouvernement du Québec | 2006 | final |
| Charlemagne-Joliette | Gouvernement du Québec | 1981 | final |
Towns with a flood study on file
Only 45% of towns in Quebec have a flood study, short of Canada’s 58%; L'Assomption 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 mapping around L'Assomption has come in steps: 2 studies from the 1980s to the 2000s.
Study dates as the NRCan inventory lists them, one count per study touching L'Assomption.
Flood studies don’t enter the grade; they are listed so you can open the official map for L'Assomption.
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.
Shaking is L'Assomption’s costliest hazard: $0.18 a year per $1,000
Expected yearly building losses from earthquakes, from Natural Resources Canada’s model.
The typical town loses $0.030 a year to shaking; L'Assomption loses $0.18, 5.9 times as much.
Shaking damage a year per $1,000 of building value
At $0.18, L'Assomption is above the typical town in Quebec ($0.14); La Pocatière has the most 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.
14% of Canada’s 2,611 towns expect more shaking damage than L'Assomption, 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 L'Assomption 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).
Little radon around L'Assomption: 3.9% of area homes over the guideline
Long-term radon tests in homes across the survey area, against Health Canada’s guideline. · Area-wide: radon tests, counted over the Lanaudiere health region
At 3.9% over the guideline, the area around L'Assomption is under the typical Canadian town’s 6.6%.
Tested homes over 200 Bq/m³
Over 600 Bq/m³
Radon runs lower around L'Assomption than in most towns in Quebec: 3.9% against 8.2%.
Health Canada radon survey (2009–2011), by 2007 health region; medians of towns of 2,500 people or more.
L'Assomption is in the lowest band, with 37% of Canada’s 2,611 towns: under 5% of tests over the guideline, while 63% 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.
Radon varies from house to house in L'Assomption, 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 L'Assomption
Alerts for L'Assomption 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 L'Assomption 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 L'Assomption
Wildfire band, earthquake risk, radon and flood studies for each place nearby.
| Town | Wildfire | Quake $/1,000 | Radon | Flood study |
|---|---|---|---|---|
| L'Assomption | Low | $0.18 | 3.9% | Yes |
| Saint-Sulpice 3,688 · 5.1 km | Low | $0.16 | 3.9% | Yes |
| L'Épiphanie 9,254 · 5.5 km | Low | $0.19 | 3.9% | Yes |
| Sainte-Marie-Salomé 1,296 · 9.6 km | Low | $0.18 | 3.9% | None listed |
| Verchères 5,819 · 10.0 km | Low | $0.17 | 8.2% | Yes |
| Repentigny 91,290 · 10 km | Low | $0.20 | 3.9% | Yes |
| Lavaltrie 15,996 · 11 km | Low | $0.15 | 3.9% | Yes |
Saint-Sulpice burns a little more than L'Assomption, 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 L'Assomption faces
What to do about the hazards L'Assomption 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
- 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 L'Assomption until then.
- Flood studies aren’t flood zones. Flood studies cover areas of every size, which is why the page lists them for L'Assomption without grading them.
- 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 L'Assomption.
- Earthquakes are modelled. The earthquake figure is an expected loss, not a forecast, worked out by NRCan for each census subdivision, L'Assomption’s included.
Questions about flooding and hazards in L'Assomption
Is L'Assomption at risk of wildfire?
Fire has reached 0.1% of the land around L'Assomption since 1986 (last in 2025); at low, it neither helps nor hurts the grade.
How big is the earthquake risk in L'Assomption?
NRCan’s model expects shaking to cost buildings in L'Assomption $0.18 a year for every $1,000 of their value, on average over many years.
Does L'Assomption flood?
A flood study covers L'Assomption on Canada’s Flood Map Inventory; open the owner’s map to check a street, since flood isn’t graded.
How is L'Assomption’s Hazard risk Grade worked out?
L'Assomption’s Hazard risk grade is C+, built on earthquakes and radon with a one-sided wildfire input.
Is radon a problem in L'Assomption?
Around L'Assomption, 77 survey homes were tested and 3.9% came in over 200 Bq/m³, a guide to the area, not to any one home.
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).