Photo: Steven.Pigeon · Public domainA flood study covers Oka: 1 on the national inventory, the newest from Communauté métropolitaine de Montréal
Fire seldom reaches Oka: since 1986, 0% of the land within 25 km has burned (0.000% a year). Earthquakes add more: NRCan’s model puts building losses at $0.13 a year per $1,000 of value, against $0.030 for the typical town. Radon is higher than usual: 10% of tested homes in the survey area topped the guideline, against 6.6% for the typical town. Hazard risk gives Oka a grade of C−, from earthquakes and radon alone.
What stands out about Oka’s hazards
For Oka, from NRCan’s seismic model, Health Canada’s radon survey, the national burned-area record and the flood map inventory.
What Oka faces
Each hazard against its own yardstick; meters run from low to high on that yardstick.
Wildfire
Earthquakes
Radon
Flood study
Hazard risk in Oka: C−
The grade weighs Oka’s seismic risk and radon equally, and wildfire is one-sided: a high band counts against a town, a low one earns nothing.
Its place: #407 of 507 in Quebec and #2,386 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 Oka: 0% of the land within 25 km burned since 1986, 0% within 5 km
Past fire around Oka’s homes, from the national burned-area record, with the fuel within 5 km.
Next to the typical Canadian town (0.000% a year), Oka’s 0.000% is in the low band.
Little near Oka’s homes can carry a forest fire; only 4.2% of the land within 5 km is forest fuel, and 4.8% 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
Little or nothing burns around Oka in a typical year; 144 of the 513 towns in Quebec share that, and 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.
Measured against 2,610 towns, Oka is in the largest group, low (92%), and at its floor, while 7.5% rank higher.
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.
Oka is on the flood map inventory: 1 study, by Communauté métropolitaine de Montréal
What Canada’s Flood Map Inventory lists for Oka: who studied flooding and where to see their maps.
The flood study touching Oka is Communauté métropolitaine de Montréal’s, dated 2008; its own map shows the zones street by street.
| Study | By | Year | Status |
|---|---|---|---|
| Montréal-Argenteuil-Deux-Montagnes-Vaudreuil-Soulanges | Communauté métropolitaine de Montréal | 2008 | final |
Towns with a flood study on file
Mapping in Quebec reaches 45% of towns, Oka 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.
Nothing here counts toward Risk; the studies are pointers to the maps their owners keep for Oka.
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 Oka $0.13 per $1,000 a year
Expected yearly building losses from earthquakes, from Natural Resources Canada’s model.
At $0.13 per $1,000, Oka carries roughly 4.3 times the typical Canadian town’s earthquake risk ($0.030).
Shaking damage a year per $1,000 of building value
Earthquake risk around Oka ($0.13) matches the middle in Quebec ($0.14), far from La Pocatière’s $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.
22% of Canada’s 2,611 towns expect more shaking damage than Oka, 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).
What a quake does after the shaking, fire, landslides, tsunami, falls outside NRCan’s figure for Oka.
Natural Resources Canada, Canada’s Seismic Risk Model (2022), by census subdivision (2016 boundaries; a few 2021 subdivisions take their residents’ mean).
10% of homes tested around Oka are over the radon guideline
Long-term radon tests in homes across the survey area, against Health Canada’s guideline. · Source area for radon tests: the Laurentides health region
At 10% over the guideline, the area around Oka beats the typical Canadian town’s 6.6%.
Tested homes over 200 Bq/m³
Over 600 Bq/m³
Oka’s area, at 10%, is above the median in Quebec (8.2%), and 1.3% of its tests passed 600 Bq/m³.
Health Canada radon survey (2009–2011), by 2007 health region; medians of towns of 2,500 people or more.
More high tests than most: Oka sits in a band that only 22% of Canada’s 2,611 towns share, with 4.6% above.
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 Oka, 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 Oka
Environment and Climate Change Canada issues the weather alerts for Oka; 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. |
Smoke and fire warnings for Oka come through Environment Canada and Alert Ready; the fire map is CWFIS’s.
Weather alerts (ECCC) · Alert Ready · Fire danger and active fires (CWFIS)
Hazards in the places around Oka
Wildfire band, earthquake risk, radon and flood studies for each place nearby.
| Town | Wildfire | Quake $/1,000 | Radon | Flood study |
|---|---|---|---|---|
| Oka | Low | $0.13 | 10% | Yes |
| Kanesatake 1,872 · 3.7 km | Low | $0.10 | 10% | Yes |
| Saint-Joseph-du-Lac 7,391 · 6.7 km | Low | $0.14 | 10% | Yes |
| Hudson 5,533 · 6.8 km | Low | $0.14 | 8.2% | Yes |
| Pointe-Calumet 6,427 · 7.2 km | Low | $0.15 | 10% | Yes |
| Vaudreuil-sur-le-Lac 1,340 · 7.6 km | Low | $0.17 | 8.2% | Yes |
| Vaudreuil-Dorion 46,413 · 9.8 km | Low | $0.17 | 8.2% | Yes |
Hudson burns a little more than Oka, 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 Oka faces
What to do about the hazards Oka 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
- 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 Oka.
- Flood studies aren’t flood zones. Flood studies cover areas of every size, which is why the page lists them for Oka without grading them.
- Earthquakes are modelled. The earthquake figure is an expected loss, not a forecast, worked out by NRCan for each census subdivision, Oka’s included.
- 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 Oka until then.
Questions about flooding and hazards in Oka
Is radon a problem in Oka?
In Health Canada’s survey, 10% of 78 homes tested in Oka’s area were above 200 Bq/m³, though only a test tells you about one house.
Is Oka at risk of wildfire?
Less than most of Canada: 0% of the land within 25 km of Oka has burned since 1986, the last in 2025, a low band that leaves Risk alone.
How is Oka’s Hazard risk Grade worked out?
Oka grades C− for hazard risk, from earthquakes and radon, with wildfire counted only where it lowers the grade.
Does Oka flood?
A flood study covers Oka on Canada’s Flood Map Inventory; open the owner’s map to check a street, since flood isn’t graded.
How big is the earthquake risk in Oka?
In NRCan’s seismic model, Oka’s buildings lose $0.13 per $1,000 of value in an average year.
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).