Photo: Archives de la Ville de Montréal - VM166-R3209-2-022. · Public domainWildfire low, radon 6.8%: how Snowdon stands on hazards
Wildfire is rare near Snowdon: 0.1% of the land within 25 km has burned since 1986, a burn rate of 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. Snowdon grades C for hazard risk; wildfire is low here, so it earns no credit.
What stands out about Snowdon’s hazards
For Snowdon, from NRCan’s seismic model, Health Canada’s radon survey, the national burned-area record and the flood map inventory.
What Snowdon faces
Each hazard against its own yardstick; meters run from low to high on that yardstick.
Wildfire
Earthquakes
Radon
Flood study
Hazard risk in Snowdon: C
Earthquake risk and radon make Snowdon’s grade; wildfire can only lower it, never raise it, and flood studies are listed but not scored.
Its place: #161 of 507 in Quebec and #2,110 of 2,589 Canadian towns.
How sure: The seismic figure is a long-run average from NRCan’s model, not a prediction. Only 74 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.
Few fires near Snowdon: 0% within 5 km, 0.1% within 25 km
Past fire around Snowdon’s homes, from the national burned-area record, with the fuel within 5 km.
Around Snowdon fire takes 0.001% of the land in a typical year, the typical Canadian town 0.000%, which is low.
The 5 km ring around Snowdon’s homes is clear of burns since 1986, the nearest 8.8 km out.
Land that isn’t forest covers nearly all the ground around Snowdon: forest fuel is 0.1% within 5 km and 0.5% 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
In the upper half in Quebec but far from Mistissini (0.31%): Snowdon ranks 136th of 513, at 0.001% a year.
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.
Beside 2,610 Canadian towns, Snowdon reads low, with 92% of them; only 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.
The flood map inventory lists nothing for Snowdon
What Canada’s Flood Map Inventory lists for Snowdon: who studied flooding and where to see their maps.
Canada’s Flood Map Inventory lists no study whose area touches Snowdon, which doesn’t mean it has never been mapped.
Towns with a flood study on file
Only 45% of towns in Quebec have a flood study, short of Canada’s 58%, and Snowdon is not among them.
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 Snowdon’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.”
Shaking is Snowdon’s costliest hazard: $0.20 a year per $1,000
Expected yearly building losses from earthquakes, from Natural Resources Canada’s model.
Snowdon’s $0.20 is about 6.7 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
Snowdon’s $0.20 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.
Only 8.5% of Canada’s 2,611 towns expect more shaking damage than Snowdon.
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 Snowdon.
Natural Resources Canada, Canada’s Seismic Risk Model (2022), by census subdivision (2016 boundaries; a few 2021 subdivisions take their residents’ mean). · Area behind the earthquake risk figures: the city of Montréal
Radon about average around Snowdon: 6.8% over the guideline
Long-term radon tests in homes across the survey area, against Health Canada’s guideline.
6.8% of tested homes around Snowdon were over the guideline, much like the typical Canadian town at 6.6%. For radon tests, the only official count covers all of the Montreal health region, Snowdon included.
Tested homes over 200 Bq/m³
Over 600 Bq/m³
Around Snowdon, 6.8% of tests topped the guideline, about the same as the typical town in Quebec (8.2%).
Health Canada radon survey (2009–2011), by 2007 health region; medians of towns of 2,500 people or more.
Radon tops the guideline in a modest share of homes around Snowdon, a band holding 37% of Canada’s 2,611 towns; 26% rank 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 Snowdon, 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 Snowdon
Environment and Climate Change Canada issues the weather alerts for Snowdon; 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 Snowdon come through Environment Canada and Alert Ready; the fire map is CWFIS’s.
Weather alerts (ECCC) · Alert Ready · Fire danger and active fires (CWFIS)
How Snowdon’s neighbours compare on hazards
Wildfire band, earthquake risk, radon and flood studies for each place nearby.
| Town | Wildfire | Quake $/1,000 | Radon | Flood study |
|---|---|---|---|---|
| Snowdon | Low | $0.20 | 6.8% | None listed |
| Hampstead 7,464 · 1.1 km | Low | $0.22 | 6.8% | None listed |
| Côte-Saint-Antoine 20,415 · 1.4 km | Low | $0.20 | 6.8% | None listed |
| Édouard-Montpetit 20,601 · 1.5 km | Low | $0.20 | 6.8% | None listed |
| Savane 32,028 · 1.6 km | Low | $0.20 | 6.8% | None listed |
| Upper Lachine 21,130 · 2.2 km | Low | $0.20 | 6.8% | None listed |
| Westmount 20,377 · 2.4 km | Low | $0.12 | 6.8% | None listed |
None of the places around has more fire nearby than Snowdon (low); Hampstead comes closest (low).
Radon is the survey area’s figure, so neighbours in one area share it.
Get ready for what Snowdon faces
Practical steps for Snowdon’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?
- Ask the municipality for flood maps.
- Are flood and wildfire insured?
- Is earthquake cover included?
What this data can and can’t tell you
- 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 Snowdon sits in.
- Earthquakes are modelled. The earthquake figure is an expected loss, not a forecast, worked out by NRCan for each census subdivision, Snowdon’s included.
- 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 Snowdon floods.
- 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 Snowdon.
Questions about flooding and hazards in Snowdon
How is Snowdon’s Hazard risk Grade worked out?
Snowdon grades C for hazard risk, from earthquakes and radon, with wildfire counted only where it lowers the grade.
Does Snowdon flood?
No study on Canada’s Flood Map Inventory covers Snowdon (0), which doesn’t mean it has never been mapped, so ask the municipality.
How big is the earthquake risk in Snowdon?
NRCan’s model expects shaking to cost buildings in Snowdon $0.20 a year for every $1,000 of their value, on average over many years.
Is Snowdon at risk of wildfire?
Not much by Canadian standards: Snowdon’s band is low, with 0.1% of the land within 25 km burned since 1986 (last in 2025), so wildfire doesn’t change its grade.
Is radon a problem in Snowdon?
6.8% of the 74 homes Health Canada tested around Snowdon 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).