Photo: Gaétan Veillette · CC BY-SA 4.0Deux-Montagnes faces more hazards than 89% of Canadian towns
Wildfire isn’t Deux-Montagnes’ worry: 0% of the land within 25 km burned since 1986 (0.001% a year). Shaking is a bigger worry than in most places, at $0.20 a year per $1,000 of building value ($0.030 typical). More homes than usual carry radon here, 10% over the guideline where the typical town has 6.6%. Hazard risk gives Deux-Montagnes a grade of D, from earthquakes and radon alone.
What stands out about Deux-Montagnes’s hazards
For Deux-Montagnes, from NRCan’s seismic model, Health Canada’s radon survey, the national burned-area record and the flood map inventory.
What Deux-Montagnes faces
Each hazard against its own yardstick; meters run from low to high on that yardstick.
Wildfire
Earthquakes
Radon
Flood study
Deux-Montagnes grades D for hazard risk
Earthquake risk and radon make Deux-Montagnes’ grade; wildfire can only lower it, never raise it, and flood studies are listed but not scored.
Its place: #467 of 507 in Quebec and #2,467 of 2,589 Canadian towns.
How sure: The seismic figure is a long-run average from NRCan’s model, not a prediction. Only 78 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 Deux-Montagnes: 0% of the land within 25 km burned since 1986, 0% within 5 km
Past fire around Deux-Montagnes’ homes, from the national burned-area record, with the fuel within 5 km.
In a typical year 0.001% of the land near Deux-Montagnes burns; the typical Canadian town sees 0.000%, and both are low.
Since 1986 the nearest fire to Deux-Montagnes’ homes came within 6.7 km, never inside 5 km.
With 0.4% forest fuel within 5 km and 2.8% within 25 km, the land around Deux-Montagnes gives a fire little to burn.
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, Deux-Montagnes 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 Deux-Montagnes 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.
Deux-Montagnes is on the flood map inventory: 2 studies, latest by Communauté métropolitaine de Montréal
What Canada’s Flood Map Inventory lists for Deux-Montagnes: who studied flooding and where to see their maps.
Communauté métropolitaine de Montréal and others have studied flooding in areas that include Deux-Montagnes: 2 studies, the latest from 2008.
| Study | By | Year | Status |
|---|---|---|---|
| Montréal-Argenteuil-Deux-Montagnes-Vaudreuil-Soulanges | Communauté métropolitaine de Montréal | 2008 | final |
| Moulins-Thérèse-De-Blainville-Deux-Montagnes-Laval | Gouvernement du Québec | 2006 | final |
Towns with a flood study on file
Flood maps are thinner in Quebec, 45% of towns against 58% nationally, but Deux-Montagnes has one.
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 Deux-Montagnes’ 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 Deux-Montagnes $0.20 per $1,000 a year
Expected yearly building losses from earthquakes, from Natural Resources Canada’s model.
Deux-Montagnes’ $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; Deux-Montagnes 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.
More earthquake risk than most: only 12% of Canada’s 2,611 towns are above Deux-Montagnes.
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 Deux-Montagnes 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).
Test for radon in Deux-Montagnes: 10% of area homes were over the guideline
Long-term radon tests in homes across the survey area, against Health Canada’s guideline.
Deux-Montagnes’ survey area reads 10% over the guideline, well past the typical Canadian town’s 6.6%. For radon tests, the only official count covers all of the Laurentides health region, Deux-Montagnes included.
Tested homes over 200 Bq/m³
Over 600 Bq/m³
Around Deux-Montagnes, 10% of tests were over 200 Bq/m³ and 1.3% over 600, against a median of 8.2% in Quebec.
Health Canada radon survey (2009–2011), by 2007 health region; medians of towns of 2,500 people or more.
One test in ten or more tops the guideline around Deux-Montagnes, as in 22% of Canada’s 2,611 towns; 4.6% go 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.
Radon varies from house to house in Deux-Montagnes, 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 Deux-Montagnes
Environment and Climate Change Canada issues the weather alerts for Deux-Montagnes; 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. |
For fires near Deux-Montagnes, the national fire information system maps danger and active fires daily; local authorities give any evacuation order.
Weather alerts (ECCC) · Alert Ready · Fire danger and active fires (CWFIS)
How Deux-Montagnes’ neighbours compare on hazards
Wildfire band, earthquake risk, radon and flood studies for each place nearby.
| Town | Wildfire | Quake $/1,000 | Radon | Flood study |
|---|---|---|---|---|
| Deux-Montagnes | Low | $0.20 | 10% | Yes |
| Laval-Ouest 11,034 · 2.3 km | Low | $0.21 | 12% | Yes |
| Saint-Eustache 47,562 · 3.1 km | Low | $0.20 | 10% | Yes |
| Sainte-Marthe-sur-le-Lac 21,949 · 3.5 km | Low | $0.19 | 10% | Yes |
| L'Île-Bizard–Sainte-Geneviève 18,885 · 5.7 km | Low | $0.20 | 6.8% | Yes |
| Fabreville 48,457 · 6.8 km | Low | $0.21 | 12% | Yes |
| Sainte-Dorothée 38,183 · 6.9 km | Low | $0.21 | 12% | Yes |
Nowhere around Deux-Montagnes burns more: Laval-Ouest, the closest rival, is low to its low.
Radon is the survey area’s figure, so neighbours in one area share it.
Get ready for what Deux-Montagnes faces
Practical steps for Deux-Montagnes’ 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. Seismic risk is NRCan’s model of yearly building losses from shaking, averaged over many years and given for Deux-Montagnes’ census subdivision (a neighbourhood shows its city’s).
- Flood studies aren’t flood zones. Flood studies cover areas of every size, which is why the page lists them for Deux-Montagnes without grading them.
- Wildfire counts one way. For Deux-Montagnes, wildfire means how much nearby land burned in the past forty years, a one-way input that can pull Risk down and nothing more.
- 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 Deux-Montagnes until then.
Questions about flooding and hazards in Deux-Montagnes
How big is the earthquake risk in Deux-Montagnes?
NRCan’s model expects shaking to cost buildings in Deux-Montagnes $0.20 a year for every $1,000 of their value, on average over many years.
How is Deux-Montagnes’s Hazard risk Grade worked out?
Deux-Montagnes grades D for hazard risk, from earthquakes and radon, with wildfire counted only where it lowers the grade.
Is radon a problem in Deux-Montagnes?
10% of the 78 homes Health Canada tested around Deux-Montagnes topped the guideline; your own house needs its own test.
Does Deux-Montagnes flood?
A flood study covers Deux-Montagnes on Canada’s Flood Map Inventory; open the owner’s map to check a street, since flood isn’t graded.
Is Deux-Montagnes at risk of wildfire?
Not much by Canadian standards: Deux-Montagnes’ band is low, with 0% of the land within 25 km burned since 1986 (last in 2025), so wildfire doesn’t change its grade.
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).