Photo: Veillg1 · CC0A flood study covers Lachute: 1 on the national inventory, the newest from Gouvernement du Québec
Wildfire barely registers for Lachute, at 0% of the land within 25 km since 1986 (0.001% a year). Seismic risk runs high: $0.13 of expected damage per $1,000 of buildings a year, the typical town $0.030. More homes than usual carry radon here, 10% over the guideline where the typical town has 6.6%. Lachute grades C− for hazard risk; wildfire is low here, so it earns no credit.
What stands out about Lachute’s hazards
For Lachute, from NRCan’s seismic model, Health Canada’s radon survey, the national burned-area record and the flood map inventory.
What Lachute faces
Each hazard against its own yardstick; meters run from low to high on that yardstick.
Wildfire
Earthquakes
Radon
Flood study
Lachute grades C− for hazard risk
Earthquake risk and radon make Lachute’s grade; wildfire can only lower it, never raise it, and flood studies are listed but not scored.
Its place: #408 of 507 in Quebec and #2,387 of 2,589 Canadian towns.
How sure: Earthquake losses are a model’s expectation over many years, not a forecast for any one. 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 Lachute: 0% of the land within 25 km burned since 1986, 0% within 5 km
Past fire around Lachute’s homes, from the national burned-area record, with the fuel within 5 km.
Low: the land around Lachute burns at 0.001% a year, where the typical Canadian town sees 0.000%.
The closest burn since 1986 lies 5.4 km from Lachute’s homes, none within 5 km.
About as much forest grows next to Lachute’s homes (17% within 5 km) as across 25 km (13%).
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, Lachute 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.
Beside 2,610 Canadian towns, Lachute 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.
Lachute is on the flood map inventory: 1 study, by Gouvernement du Québec
What Canada’s Flood Map Inventory lists for Lachute: who studied flooding and where to see their maps.
The flood study touching Lachute is Gouvernement du Québec’s, dated 1992; its own map shows the zones street by street.
| Study | By | Year | Status |
|---|---|---|---|
| Lachute-St-Jérôme | Gouvernement du Québec | 1992 | final |
Towns with a flood study on file
Flood maps are thinner in Quebec, 45% of towns against 58% nationally, but Lachute has one.
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 Lachute.
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 Lachute $0.13 per $1,000 a year
Expected yearly building losses from earthquakes, from Natural Resources Canada’s model.
Roughly 4.4 times the typical $0.030: Lachute’s $0.13 marks real seismic exposure.
Shaking damage a year per $1,000 of building value
About level with the typical town in Quebec: Lachute’s $0.13 against $0.14; 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.
Lachute sits above most of Canada’s 2,611 towns on earthquake risk; 22% are 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).
For Lachute the model prices shaking damage to buildings, nothing more.
Natural Resources Canada, Canada’s Seismic Risk Model (2022), by census subdivision (2016 boundaries; a few 2021 subdivisions take their residents’ mean).
Radon runs high around Lachute: 10% of tested homes over the guideline
Long-term radon tests in homes across the survey area, against Health Canada’s guideline. · Shared with the rest of the Laurentides health region: radon tests
More homes than usual test high around Lachute: 10% against 6.6% for the typical Canadian town.
Tested homes over 200 Bq/m³
Over 600 Bq/m³
More homes top the guideline around Lachute (10%) than in the typical town in Quebec (8.2%); 1.3% went over 600.
Health Canada radon survey (2009–2011), by 2007 health region; medians of towns of 2,500 people or more.
The 10–20% band holds 22% of Canada’s 2,611 towns, Lachute among them; 4.6% 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.
Whatever Lachute’s area share, the reading that matters is your own home’s, over a winter.
Health Canada, Cross-Canada Survey of Radon Concentrations in Homes (2009–2011).
Where to get warnings in Lachute
Environment and Climate Change Canada issues the weather alerts for Lachute; 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 Lachute, 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 Lachute’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 |
|---|---|---|---|---|
| Lachute | Low | $0.13 | 10% | Yes |
| Brownsburg-Chatham 8,466 · 6.4 km | Low | $0.12 | 10% | None listed |
| Saint-André-d'Argenteuil 3,300 · 9.8 km | Low | $0.14 | 10% | Yes |
| Gore 2,756 · 12 km | Low | $0.097 | 10% | None listed |
| East Hawkesbury 3,787 · 16 km | Low | $0.20 | 6.1% | None listed |
| Saint-Placide 1,751 · 17 km | Low | $0.17 | 10% | Yes |
Gore burns a little more than Lachute, 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 Lachute faces
Practical steps for Lachute’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
- Flood studies aren’t flood zones. The flood inventory points to maps; it is incomplete and not the official source, so ask the municipality about any street in Lachute.
- 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 Lachute.
- Radon is a survey. Health Canada’s survey tested some 14,000 homes over three months; until postal-area boundaries are loaded, Lachute takes its 2007 health region’s share.
- Earthquakes are modelled. The earthquake figure is an expected loss, not a forecast, worked out by NRCan for each census subdivision, Lachute’s included.
Questions about flooding and hazards in Lachute
How big is the earthquake risk in Lachute?
In NRCan’s seismic model, Lachute’s buildings lose $0.13 per $1,000 of value in an average year.
Is radon a problem in Lachute?
The area’s survey found 10% of 78 tested homes above Health Canada’s guideline, so a three-month test is worth doing in Lachute.
Is Lachute at risk of wildfire?
Some, but Lachute’s low band (0% of nearby land burned since 1986, latest 2024) is short of the level that counts.
How is Lachute’s Hazard risk Grade worked out?
Lachute’s Hazard risk grade is C−, built on earthquakes and radon with a one-sided wildfire input.
Does Lachute flood?
The inventory lists a study touching Lachute; whether a given street floods is on that map, not in 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).