Photo: NickCibroit · CC BY-SA 4.0La Prairie is on Canada’s flood inventory: 3 listed, led by municipalité de Saint-Philippe
Fire seldom reaches La Prairie: since 1986, 0% of the land within 25 km has burned (0.001% a year). Earthquakes add more: NRCan’s model puts building losses at $0.21 a year per $1,000 of value, against $0.030 for the typical town. La Prairie’s survey area, 8.2% over the radon guideline, is close to the typical town’s 6.6%. La Prairie grades C− for hazard risk; wildfire is low here, so it earns no credit.
What stands out about La Prairie’s hazards
Four national sources, each read for La Prairie: earthquakes, radon, past fires and flood studies.
What La Prairie faces
Each hazard against its own yardstick; meters run from low to high on that yardstick.
Wildfire
Earthquakes
Radon
Flood study
Hazard risk in La Prairie: C−
Seismic risk and radon set La Prairie’s grade, wildfire can drag it down, and flood mapping stays out of it.
Its place: #376 of 507 in Quebec and #2,352 of 2,589 Canadian towns.
How sure: Earthquake losses are a model’s expectation over many years, not a forecast for any one. Small fires and grass fires are largely missing from the national burned-area record.
Little of the land around La Prairie has burned: 0.3% within 5 km, 0% within 25 km since 1986
Fires mapped since 1986 around where La Prairie’s residents live, and the fuel next to their homes.
Low: the land around La Prairie burns at 0.001% a year, where the typical Canadian town sees 0.000%.
Land that isn’t forest covers nearly all the ground around La Prairie: forest fuel is 0.3% within 5 km and 0.4% 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
La Prairie burns at 0.001% a year, 136th of 513 towns in Quebec; the leader, Mistissini, reaches 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.
Some fire is mapped around La Prairie, but not enough to leave the low band, where 92% of Canada’s 2,610 towns are; 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.
3 flood studies cover La Prairie, the newest from municipalité de Saint-Philippe
Flood studies whose area touches La Prairie, from NRCan’s inventory, each linked to its owner.
municipalité de Saint-Philippe and others have studied flooding in areas that include La Prairie: 3 studies, the latest from 2012.
| Study | By | Year | Status |
|---|---|---|---|
| St-Philippe | municipalité de Saint-Philippe | 2012 | final |
| St-Philippe | Gouvernement du Québec | 2006 | final |
| Prairie-Longueuil | 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 La Prairie has one.
NRCan Canada Flood Map Inventory: a study footprint touching the town’s boundary; towns of 2,500 people or more.
The busiest decade for flood studies around La Prairie was the 2000s (2 of 3); they run from the 2000s to the 2010s.
Study dates as the NRCan inventory lists them, one count per study touching La Prairie.
Nothing here counts toward Risk; the studies are pointers to the maps their owners keep for La Prairie.
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 La Prairie $0.21 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.
La Prairie’s $0.21 is about 6.9 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; La Prairie expects $0.21, 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.
La Prairie is in the top tenth of Canada’s 2,611 towns for earthquake risk; 7.9% rank higher.
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).
The loss is to La Prairie’s buildings alone, from ground shaking; infrastructure and secondary hazards are left out.
Natural Resources Canada, Canada’s Seismic Risk Model (2022), by census subdivision (2016 boundaries; a few 2021 subdivisions take their residents’ mean).
Radon about average around La Prairie: 8.2% over the guideline
Health Canada’s survey of long-term home tests: the share above the 200 Bq/m³ guideline. · Radon tests for the Monteregie health region
At 8.2% over the guideline, the area around La Prairie is about level with the typical Canadian town’s 6.6%.
Tested homes over 200 Bq/m³
Over 600 Bq/m³
Around La Prairie, 8.2% 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.
Between 5% and 10% of tests over the guideline: La Prairie, and 37% of Canada’s 2,611 towns; 26% are 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.
The share describes the area, not a house: in La Prairie as anywhere, test to be sure.
Health Canada, Cross-Canada Survey of Radon Concentrations in Homes (2009–2011).
Weather and fire alerts for La Prairie
Environment and Climate Change Canada issues the weather alerts for La Prairie; 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 La Prairie, 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 La Prairie’s neighbours compare on hazards
The same four hazards for the places next door.
| Town | Wildfire | Quake $/1,000 | Radon | Flood study |
|---|---|---|---|---|
| La Prairie | Low | $0.21 | 8.2% | Yes |
| Candiac 24,920 · 4.2 km | Low | $0.20 | 8.2% | Yes |
| Brossard 97,597 · 5.1 km | Low | $0.22 | 8.2% | Yes |
| Saint-Philippe 8,674 · 6.0 km | Low | $0.18 | 8.2% | Yes |
| Delson 8,802 · 6.5 km | Low | $0.21 | 8.2% | Yes |
| Sainte-Catherine 17,782 · 6.9 km | Low | $0.22 | 8.2% | Yes |
| Ile-des-Soeurs 21,568 · 7.7 km | Low | $0.20 | 6.8% | None listed |
Brossard burns a little more than La Prairie, 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 La Prairie faces
Practical steps for La Prairie’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
- Wildfire counts one way. Wildfire is read from the national burned-area record around La Prairie’s homes since 1986, a history of fire that may lower Risk but never raises it.
- Earthquakes are modelled. NRCan models what earthquakes would cost buildings each year on average, subdivision by subdivision; La Prairie’s figure is its subdivision’s.
- Radon is a survey. About 14,000 homes were tested across Canada in 2009–2011, and the share over the guideline for La Prairie is its health region’s, the survey’s design unit.
- Flood studies aren’t flood zones. NRCan’s inventory says where flood mapping exists, not where water goes; the map’s owner is the authority for La Prairie.
Questions about flooding and hazards in La Prairie
Is La Prairie at risk of wildfire?
Not much by Canadian standards: La Prairie’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.
Is radon a problem in La Prairie?
8.2% of the 110 homes Health Canada tested around La Prairie topped the guideline; your own house needs its own test.
Does La Prairie flood?
There is flood mapping for La Prairie on the national inventory, each study linked to its owner’s map, none of them graded.
How big is the earthquake risk in La Prairie?
Expected earthquake damage in La Prairie comes to $0.21 a year for each $1,000 that buildings are worth.
How is La Prairie’s Hazard risk Grade worked out?
La Prairie grades C− for hazard risk, from earthquakes and radon, with wildfire counted only where it lowers the 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).