Photo: P199 · CC BY-SA 3.0Hazard risk in Keswick is lower than in 92% of Canadian towns
Little of the land around Keswick has burned: 0% within 25 km since 1986, or 0.001% a year. Seismic risk in Keswick sits near the middle: $0.024 of expected damage per $1,000 of buildings a year, the typical town $0.030. Radon is lower than usual: 0% of tested homes in the survey area topped the guideline, against 6.6% for the typical town. Hazard risk gives Keswick a grade of A; its wildfire band pulls it down.
What stands out about Keswick’s hazards
Four national sources, each read for Keswick: earthquakes, radon, past fires and flood studies.
What Keswick faces
Each hazard against its own yardstick; meters run from low to high on that yardstick.
Wildfire
Earthquakes
Radon
Flood study
Keswick grades A for hazard risk
For Keswick, Risk will be the average of earthquakes and radon, with wildfire added only if it makes the average worse.
Its place: #36 of 866 in Ontario and #288 of 2,589 Canadian towns.
How sure: The seismic figure is a long-run average from NRCan’s model, not a prediction. Small fires and grass fires are largely missing from the national burned-area record.
Little of the land around Keswick has burned: 0.2% within 5 km, 0% within 25 km since 1986
Past fire around Keswick’s homes, from the national burned-area record, with the fuel within 5 km.
Low by Canadian standards: 0.001% of the land a year around Keswick, 0.000% for the typical Canadian town.
More forest grows near Keswick’s homes (20% within 5 km) than across 25 km (14%).
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
In the top quarter in Ontario: Keswick ranks 83rd of 871 at 0.001% a year, with Sioux Lookout first 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.
7.5% of Canada’s 2,610 towns burn fast enough to rank moderate or above; Keswick stays low, with 92%.
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 Keswick
What Canada’s Flood Map Inventory lists for Keswick: who studied flooding and where to see their maps.
Canada’s Flood Map Inventory lists no study whose area touches Keswick, which doesn’t mean it has never been mapped.
Towns with a flood study on file
Keswick has no flood study on file, though 69% of towns in Ontario do (Canada: 58%).
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 Keswick’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.”
Expected shaking damage in Keswick: $0.024 a year per $1,000
Expected yearly building losses from earthquakes, from Natural Resources Canada’s model.
Keswick’s $0.024 is close to the typical town’s $0.030 (0.8 times as much).
Shaking damage a year per $1,000 of building value
The typical town in Ontario expects $0.043 a year in shaking damage; Keswick expects less, $0.024, and Alexandria the most, $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.
Keswick sits mid-range among Canada’s 2,611 towns: 54% expect more shaking damage.
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 Keswick’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).
Little radon around Keswick: 0% of area homes over the guideline
Long-term radon tests in homes across the survey area, against Health Canada’s guideline.
At 0% over the guideline, the area around Keswick is under the typical Canadian town’s 6.6%.
Tested homes over 200 Bq/m³
Over 600 Bq/m³
Radon runs lower around Keswick than in most towns in Ontario: 0% against 4%.
Health Canada radon survey (2009–2011), by 2007 health region; medians of towns of 2,500 people or more.
Under 5% puts Keswick with 37% of Canada’s 2,611 towns; 63% have more high tests.
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 Keswick 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). · Not measured by town: radon tests (the York Regional Health Unit)
Weather and fire alerts for Keswick
Environment and Climate Change Canada issues the weather alerts for Keswick; 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. |
In fire season, check CWFIS for danger and active fires around Keswick, and listen to local authorities for orders.
Weather alerts (ECCC) · Alert Ready · Fire danger and active fires (CWFIS)
Hazards in the places around Keswick
Wildfire band, earthquake risk, radon and flood studies for each place nearby.
| Town | Wildfire | Quake $/1,000 | Radon | Flood study |
|---|---|---|---|---|
| Keswick | Low | $0.024 | 0% | None listed |
| Innisfil 50,686 · 12 km | Low | $0.019 | 0.9% | None listed |
| East Gwillimbury 42,989 · 18 km | Low | $0.023 | 0% | None listed |
Innisfil (low) has the heaviest fire record of Keswick’s neighbours, and Keswick (low) matches or beats it.
Radon is the survey area’s figure, so neighbours in one area share it.
Get ready for what Keswick faces
Practical steps for Keswick’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.
- Clear needles and wood nearby.
- Keep a grab-and-go bag ready.
- In smoke, stay in; filter air.
- Has it had a radon test?
- Ask the municipality for flood maps.
- Are flood and wildfire insured?
What this data can and can’t tell you
- Wildfire counts one way. Wildfire is read from the national burned-area record around Keswick’s homes since 1986, a history of fire that may lower Risk but never raises it.
- Radon is a survey. Radon figures pool the survey’s home tests by area: postal areas once their boundaries arrive, the 2007 health region around Keswick until then.
- Flood studies aren’t flood zones. Flood studies cover areas of every size, which is why the page lists them for Keswick without grading them.
- Earthquakes are modelled. NRCan models what earthquakes would cost buildings each year on average, subdivision by subdivision; Keswick’s figure is its subdivision’s.
Questions about flooding and hazards in Keswick
Is Keswick at risk of wildfire?
Some, but Keswick’s low band (0% of nearby land burned since 1986, latest 2006) is short of the level that counts.
How is Keswick’s Hazard risk Grade worked out?
Hazard risk gives Keswick A, weighing earthquakes and radon and counting wildfire only against it.
Is radon a problem in Keswick?
The area’s survey found 0% of 95 tested homes above Health Canada’s guideline, so a three-month test is worth doing in Keswick.
How big is the earthquake risk in Keswick?
In NRCan’s seismic model, Keswick’s buildings lose $0.024 per $1,000 of value in an average year.
Does Keswick flood?
The inventory has 0 studies for Keswick, and an empty list isn’t a clean bill: the municipality holds any flood maps.
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).