Photo: P199 · CC BY-SA 3.0Long Sault is on Canada’s flood inventory: 8 listed, led by Raisin Region Conservation Authority
The national fire record shows next to nothing around Long Sault, 0% of the land within 25 km since 1986 (0.000% 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). Long Sault’s survey area, 6.1% over the radon guideline, is close to the typical town’s 6.6%. Hazard risk gives Long Sault a grade of C, from earthquakes and radon alone.
What stands out about Long Sault’s hazards
Four national sources, each read for Long Sault: earthquakes, radon, past fires and flood studies.
What Long Sault faces
Each hazard against its own yardstick; meters run from low to high on that yardstick.
Wildfire
Earthquakes
Radon
Flood study
Hazard risk in Long Sault: C
Seismic risk and radon set Long Sault’s grade, wildfire can drag it down, and flood mapping stays out of it.
Its place: #832 of 866 in Ontario and #2,066 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.
Few fires near Long Sault: 0% within 5 km, 0% within 25 km
Fires mapped since 1986 around where Long Sault’s residents live, and the fuel next to their homes.
A burn rate of 0.000% a year keeps Long Sault in the low band (the typical Canadian town: 0.000%).
Near or far, forest fuel covers a similar share around Long Sault: 7.1% within 5 km and 5.8% 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 Ontario · highest of 871
Sioux Lookout has the highest burn rate in Ontario, 0.16% a year; around Long Sault, as around 638 of the 871 towns, it rounds to zero.
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.
Long Sault shares the low band with 92% of Canada’s 2,610 towns, its burn rate rounding to nothing; 7.5% burn faster.
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.
8 flood studies cover Long Sault, the newest from Raisin Region Conservation Authority
Flood studies whose area touches Long Sault, from NRCan’s inventory, each linked to its owner.
8 studies on the inventory touch Long Sault, the newest Raisin Region Conservation Authority’s from 2024, and their areas can be large, so they say maps exist, not that the town floods.
| Study | By | Year | Status |
|---|---|---|---|
| Eastman Drain 2024 | Raisin Region Conservation Authority | 2024 | final |
| Raisin River and St. Lawrence River Floodplain Mapping Update | Raisin Region Conservation Authority | 2020 | final · not public |
| South Branch Raisin River Storm Water Management Study | Raisin Region Conservation Authority | 2002 | final · not public |
| St. Lawrence River Floodline Re-Mapping Study | Raisin Region Conservation Authority | 1994 | final · not public |
| Flood Plain Mapping Study - Main and North Branches Raisin River | Raisin Region Conservation Authority | 1987 | final · not public |
| South Branch - Raisin River Flood and Fill Line Mapping | Raisin Region Conservation Authority | 1984 | final · not public |
| Flood Plain Mapping Study of Hoople Creek | Raisin Region Conservation Authority | 1982 | final · not public |
| Water Management Study of South Raisin River | Raisin Region Conservation Authority | 1980 | final · not public |
Towns with a flood study on file
Its flood study puts Long Sault with 69% of towns in Ontario; Canada’s share is 58%.
NRCan Canada Flood Map Inventory: a study footprint touching the town’s boundary; towns of 2,500 people or more.
Mapping around Long Sault began in the 1980s; the 1980s saw the most work (4 of 8 studies), the latest in the 2020s.
Study dates as the NRCan inventory lists them, one count per study touching Long Sault.
Flood studies don’t enter the grade; they are listed so you can open the official map for Long Sault.
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.
Shaking is Long Sault’s costliest hazard: $0.20 a year per $1,000
NRCan’s seismic risk model: the damage shaking is expected to do to buildings each year, on average over many years.
Long Sault’s $0.20 is about 6.6 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
Above the middle in Ontario: Long Sault’s $0.20 against a median of $0.043, with Alexandria highest at $0.21.
NRCan seismic risk model (2022): mean yearly building loss per $1,000 of value; medians of towns of 2,500 people or more.
12% of Canada’s 2,611 towns expect more shaking damage than Long Sault, 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).
The loss is to Long Sault’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 Long Sault: 6.1% over the guideline
Health Canada’s survey of long-term home tests: the share above the 200 Bq/m³ guideline. · Measured across the The Eastern Ontario Health Unit: radon tests
Around Long Sault, 6.1% of tested homes topped the guideline, near the typical Canadian town’s 6.6%.
Tested homes over 200 Bq/m³
Over 600 Bq/m³
Long Sault’s area, at 6.1%, is above the median in Ontario (4%), and 1% 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.
37% of Canada’s 2,611 towns share Long Sault’s band of 5 to 10%; 26% sit 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.
A survey sample isn’t a map: any home in Long Sault can be high, and a three-month test is the only way to know.
Health Canada, Cross-Canada Survey of Radon Concentrations in Homes (2009–2011).
Weather and fire alerts for Long Sault
Alerts for Long Sault come from Environment and Climate Change Canada and, for emergencies, Alert Ready.
| 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. |
Fire danger and active fires near Long Sault are mapped daily by the Canadian Wildland Fire Information System; evacuation orders come from the municipality or province.
Weather alerts (ECCC) · Alert Ready · Fire danger and active fires (CWFIS)
Hazards in the places around Long Sault
The same four hazards for the places next door.
| Town | Wildfire | Quake $/1,000 | Radon | Flood study |
|---|---|---|---|---|
| Long Sault | Low | $0.20 | 6.1% | Yes |
| Cornwall 54,346 · 16 km | Low | $0.20 | 6.1% | Yes |
| Akwesasne (Part) 59 1,947 · 17 km | Low | $0.14 | 6.1% | Yes |
The neighbour with the most fire is Cornwall (low), still no more than Long Sault (low).
Radon is the survey area’s figure, so neighbours in one area share it.
Get ready for what Long Sault faces
Practical steps for Long Sault’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 Long Sault.
- Radon is a survey. Health Canada’s survey tested some 14,000 homes over three months; until postal-area boundaries are loaded, Long Sault takes its 2007 health region’s share.
- Earthquakes are modelled. Shaking damage is modelled from the ground, the buildings and the odds of each quake, and published for whole subdivisions such as Long Sault’s.
- Wildfire counts one way. The wildfire figure is the share of land within 25 km of Long Sault’s homes burned each year from 1986 to 2025, past fire rather than a forecast, and it can only lower Risk.
Questions about flooding and hazards in Long Sault
How big is the earthquake risk in Long Sault?
Expected earthquake damage in Long Sault comes to $0.20 a year for each $1,000 that buildings are worth.
How is Long Sault’s Hazard risk Grade worked out?
Hazard risk gives Long Sault C, weighing earthquakes and radon and counting wildfire only against it.
Is Long Sault at risk of wildfire?
No meaningful wildfire history near Long Sault: 0% of nearby land since 1986, band low.
Is radon a problem in Long Sault?
6.1% of the 99 homes Health Canada tested around Long Sault topped the guideline; your own house needs its own test.
Does Long Sault flood?
The inventory lists a study touching Long Sault; 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).