Photo: Richard Mc Neil · CC BY 3.0Flood mapping exists for Terrebonne: 2 on record, latest by Gouvernement du Québec
Little of the land around Terrebonne has burned: 0% within 25 km since 1986, or 0.001% a year. Earthquakes add more: NRCan’s model puts building losses at $0.17 a year per $1,000 of value, against $0.030 for the typical town. Radon is lower than usual: 3.9% of tested homes in the survey area topped the guideline, against 6.6% for the typical town. Terrebonne grades C+ for hazard risk; wildfire is low here, so it earns no credit.
What stands out about Terrebonne’s hazards
For Terrebonne, from NRCan’s seismic model, Health Canada’s radon survey, the national burned-area record and the flood map inventory.
What Terrebonne faces
Each hazard against its own yardstick; meters run from low to high on that yardstick.
Wildfire
Earthquakes
Radon
Flood study
Hazard risk in Terrebonne: C+
For Terrebonne, Risk will be the average of earthquakes and radon, with wildfire added only if it makes the average worse.
Its place: #102 of 507 in Quebec and #1,778 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.
Wildfire is rare near Terrebonne: 0% of the land within 25 km burned since 1986, 0% within 5 km
Fires mapped since 1986 around where Terrebonne’s residents live, and the fuel next to their homes.
Low: the land around Terrebonne burns at 0.001% a year, where the typical Canadian town sees 0.000%.
About as much forest grows next to Terrebonne’s homes (7.6% within 5 km) as across 25 km (7%).
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, Terrebonne 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 Terrebonne 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.
2 flood studies cover Terrebonne, the newest from Gouvernement du Québec
Flood studies whose area touches Terrebonne, from NRCan’s inventory, each linked to its owner.
For Terrebonne the inventory points to 2 studies, most recently Gouvernement du Québec’s in 2006.
| Study | By | Year | Status |
|---|---|---|---|
| Moulins-Thérèse-De-Blainville-Deux-Montagnes-Laval | Gouvernement du Québec | 2006 | final |
| Charlemagne-Joliette | Gouvernement du Québec | 1981 | final |
Towns with a flood study on file
Mapping in Quebec reaches 45% of towns, Terrebonne among them, below the 58% across Canada.
NRCan Canada Flood Map Inventory: a study footprint touching the town’s boundary; towns of 2,500 people or more.
Flood mapping around Terrebonne 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 Terrebonne.
Flood is shown here, never graded: a study says where a map exists, not how many of Terrebonne’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 Terrebonne $0.17 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.
Terrebonne’s $0.17 is about 5.8 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
Terrebonne’s $0.17 tops the median in Quebec, $0.14, though 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.
More earthquake risk than most: only 14% of Canada’s 2,611 towns are above Terrebonne.
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).
What a quake does after the shaking, fire, landslides, tsunami, falls outside NRCan’s figure for Terrebonne.
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 Terrebonne: 3.9% of area homes over the guideline
Health Canada’s survey of long-term home tests: the share above the 200 Bq/m³ guideline.
Terrebonne’s area, at 3.9%, is below the 6.6% of the typical Canadian town, though any one home can still be high. Terrebonne doesn’t get its own radon tests figures; the ones here come from the Lanaudiere health region.
Tested homes over 200 Bq/m³
Over 600 Bq/m³
Radon runs lower around Terrebonne 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.
Few tests over the guideline: Terrebonne shares the bottom band with 37% of Canada’s 2,611 towns, below the other 63%.
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.
Health Canada advises testing every home, Terrebonne’s included, whatever the area’s figure.
Health Canada, Cross-Canada Survey of Radon Concentrations in Homes (2009–2011).
Where to get warnings in Terrebonne
Environment and Climate Change Canada issues the weather alerts for Terrebonne; 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 Terrebonne, and listen to local authorities for orders.
Weather alerts (ECCC) · Alert Ready · Fire danger and active fires (CWFIS)
Hazards in the places around Terrebonne
The same four hazards for the places next door.
| Town | Wildfire | Quake $/1,000 | Radon | Flood study |
|---|---|---|---|---|
| Terrebonne | Low | $0.17 | 3.9% | Yes |
| Mascouche 56,897 · 4.3 km | Low | $0.19 | 3.9% | Yes |
| Saint-François 15,338 · 7.9 km | Low | $0.21 | 12% | Yes |
| Bois-des-Filion 10,666 · 9.0 km | Low | $0.13 | 10% | Yes |
| Lorraine 9,721 · 10 km | Low | $0.18 | 10% | Yes |
| Marc-Aurèle-Fortin 36,220 · 11 km | Low | $0.20 | 6.8% | None listed |
| Rivière-des-Prairies 21,852 · 11 km | Low | $0.20 | 6.8% | Yes |
The neighbour with the most fire is Mascouche (low), still no more than Terrebonne (low).
Radon is the survey area’s figure, so neighbours in one area share it.
Get ready for what Terrebonne faces
Practical steps for Terrebonne’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
- Earthquakes are modelled. The earthquake figure is an expected loss, not a forecast, worked out by NRCan for each census subdivision, Terrebonne’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 Terrebonne.
- 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 Terrebonne 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 Terrebonne sits in.
Questions about flooding and hazards in Terrebonne
Is Terrebonne at risk of wildfire?
Not much by Canadian standards: Terrebonne’s band is low, with 0% of the land within 25 km burned since 1986 (last in 2025), so wildfire doesn’t change its grade.
How big is the earthquake risk in Terrebonne?
About $0.17 a year per $1,000 of building value, NRCan’s long-run expectation for Terrebonne.
Is radon a problem in Terrebonne?
3.9% of the 77 homes Health Canada tested around Terrebonne topped the guideline; your own house needs its own test.
Does Terrebonne flood?
Terrebonne’s area has been studied for flooding, and the owner’s map shows which streets lie in a zone; the grade leaves flood out.
How is Terrebonne’s Hazard risk Grade worked out?
Terrebonne’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).