Photo: R Orville Lyttle · CC BY-SA 2.0Prescott faces more hazards than 93% of Canadian towns
Wildfire isn’t Prescott’s worry: 0% of the land within 25 km burned since 1986 (0.000% a year). Shaking is a bigger worry than in most places, at $0.10 a year per $1,000 of building value ($0.030 typical). In Health Canada’s survey, 19% of homes tested in the area exceeded 200 Bq/m³ (6.6% typical). Prescott grades D for hazard risk; wildfire is low here, so it earns no credit.
What stands out about Prescott’s hazards
Four national sources, each read for Prescott: earthquakes, radon, past fires and flood studies.
What Prescott faces
Each hazard against its own yardstick; meters run from low to high on that yardstick.
Wildfire
Earthquakes
Radon
Flood study
Hazard risk in Prescott: D
Two inputs always count for Prescott, earthquakes and radon; the third, wildfire, counts only against a town.
Its place: #858 of 866 in Ontario and #2,500 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 Prescott has burned: 0% within 5 km, 0% within 25 km since 1986
Fires mapped since 1986 around where Prescott’s residents live, and the fuel next to their homes.
Prescott burns at 0.000% a year, low against 0.000% for the typical Canadian town.
8.1% of the land within 5 km of Prescott is forest fuel, close to the 12% 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
Near-zero burning puts Prescott with 638 of the 871 towns in Ontario, far below Sioux Lookout at 0.16%.
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.
The low band holds 92% of Canada’s 2,610 towns, and Prescott sits at its very bottom; only 7.5% are above it.
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.
No flood study is listed for Prescott
Flood studies whose area touches Prescott, from NRCan’s inventory, each linked to its owner.
Nationally, Prescott has no listed flood study; the municipality is the place to ask.
Towns with a flood study on file
Flood maps are common in Ontario, 69% of towns against 58% nationally, but none in the inventory touches Prescott.
NRCan Canada Flood Map Inventory: a study footprint touching the town’s boundary; towns of 2,500 people or more.
Flood studies don’t enter the grade; they are listed so you can open the official map for Prescott.
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.”
High seismic risk in Prescott: $0.10 per $1,000 of buildings a year
NRCan’s seismic risk model: the damage shaking is expected to do to buildings each year, on average over many years.
The typical town loses $0.030 a year to shaking; Prescott loses $0.10, 3.4 times as much.
Shaking damage a year per $1,000 of building value
The typical town in Ontario expects $0.043 a year; Prescott expects $0.10, and Alexandria $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.
More earthquake risk than most: only 25% of Canada’s 2,611 towns are above Prescott.
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 model counts damage to Prescott’s buildings and their occupants from shaking only: not liquefaction, landslides, tsunami or fires after a quake.
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 Prescott: 19% of tested homes over the guideline
Health Canada’s survey of long-term home tests: the share above the 200 Bq/m³ guideline.
Radon runs above the typical Canadian town (6.6%) in Prescott’s area, at 19%. Prescott doesn’t get its own radon tests figures; the ones here come from the Leeds, Grenville and Lanark District Health Unit.
Tested homes over 200 Bq/m³
Over 600 Bq/m³
Around Prescott, 19% of tests were over 200 Bq/m³ and 1.9% over 600, against a median of 4% in Ontario.
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, Prescott 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.
The share describes the area, not a house: in Prescott as anywhere, test to be sure.
Health Canada, Cross-Canada Survey of Radon Concentrations in Homes (2009–2011).
Weather and fire alerts for Prescott
Alerts for Prescott 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. |
Alert Ready carries evacuation orders for Prescott to phones; CWFIS shows the day’s fire danger.
Weather alerts (ECCC) · Alert Ready · Fire danger and active fires (CWFIS)
Hazards in the places around Prescott
The same four hazards for the places next door.
| Town | Wildfire | Quake $/1,000 | Radon | Flood study |
|---|---|---|---|---|
| Prescott | Low | $0.10 | 19% | None listed |
| Augusta 7,767 · 6.5 km | Low | $0.11 | 19% | Yes |
| Cardinal 7,952 · 14 km | Low | $0.13 | 19% | Yes |
| Brockville 23,720 · 19 km | Low | $0.077 | 19% | Yes |
Among its neighbours Prescott has the most fire on record (low); Augusta follows (low).
Radon is the survey area’s figure, so neighbours in one area share it.
Get ready for what Prescott faces
What to do about the hazards Prescott 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?
- 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. About 14,000 homes were tested across Canada in 2009–2011, and the share over the guideline for Prescott is its health region’s, the survey’s design unit.
- 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 Prescott’s.
- Wildfire counts one way. The wildfire figure is the share of land within 25 km of Prescott’s homes burned each year from 1986 to 2025, past fire rather than a forecast, and it can only lower Risk.
- 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 Prescott.
Questions about flooding and hazards in Prescott
How big is the earthquake risk in Prescott?
Expected earthquake damage in Prescott comes to $0.10 a year for each $1,000 that buildings are worth.
How is Prescott’s Hazard risk Grade worked out?
Prescott grades D for hazard risk, from earthquakes and radon, with wildfire counted only where it lowers the grade.
Is radon a problem in Prescott?
Around Prescott, 108 survey homes were tested and 19% came in over 200 Bq/m³, a guide to the area, not to any one home.
Is Prescott at risk of wildfire?
Very little by the national record: Prescott’s band is low, with 0% of the land within 25 km burned since 1986, so wildfire doesn’t change its grade.
Does Prescott flood?
With 0 studies on the inventory, Prescott’s flood risk is unmapped nationally; check with the municipality before buying.
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).