Photo: The Town of Ajax · CC BY 3.0Few places are as safe from hazards as Ajax: it beats 85% of Canadian towns
For Ajax, wildfire history is close to nil: 0% of nearby land since 1986, 0.001% a year. For earthquakes Ajax is middling, $0.042 a year per $1,000 against $0.030 for the typical town. Radon is lower than usual: 0% of tested homes in the survey area topped the guideline, against 6.6% for the typical town. Ajax grades A for hazard risk, with wildfire counted against it.
What stands out about Ajax’s hazards
For Ajax, from NRCan’s seismic model, Health Canada’s radon survey, the national burned-area record and the flood map inventory.
What Ajax faces
Each hazard against its own yardstick; meters run from low to high on that yardstick.
Wildfire
Earthquakes
Radon
Flood study
Hazard risk in Ajax: A
Two inputs always count for Ajax, earthquakes and radon; the third, wildfire, counts only against a town.
Its place: #229 of 866 in Ontario and #571 of 2,589 Canadian towns.
How sure: Earthquake losses are a model’s expectation over many years, not a forecast for any one. The burned-area record misses fires under about 10 ha and most grass and farm fires.
Wildfire is rare near Ajax: 0% of the land within 25 km burned since 1986, 0% within 5 km
Fires mapped since 1986 around where Ajax’s residents live, and the fuel next to their homes.
In a typical year 0.001% of the land near Ajax burns; the typical Canadian town sees 0.000%, and both are low.
Nothing inside 5 km of Ajax’s homes has burned since 1986, and the nearest scar is 6.7 km off.
Near or far, forest fuel covers a similar share around Ajax: 11% within 5 km and 11% 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 burns fastest in Ontario at 0.16% a year; Ajax, at 0.001%, ranks 83rd of 871.
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, Ajax 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.
Flooding around Ajax is mapped in 4 studies, the newest by Central Lake Ontario Conservation Authority
Flood studies whose area touches Ajax, from NRCan’s inventory, each linked to its owner.
Central Lake Ontario Conservation Authority and others have studied flooding in areas that include Ajax: 4 studies, the latest from 2025.
| Study | By | Year | Status |
|---|---|---|---|
| Lynde Creek Watershed | Central Lake Ontario Conservation Authority | 2025 | final |
| Toronto Floodline Consolidation | Toronto Regional Conservation Authority | 2021 | final |
| Whitby Coastal Flood Hazard, Risk Assessment and Municipal Class Environmental Assessment | Town of Whitby | 2021 | final |
| Duffins Creek | Toronto and Region Conservation Authority | 2020 | final |
Towns with a flood study on file
Mapping in Ontario reaches 69% of towns, Ajax included, beside 58% across Canada.
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 Ajax’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.”
Natural Resources Canada, Canada Flood Map Inventory; links go to each study’s owner.
Expected shaking damage in Ajax: $0.042 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.
With $0.042 of shaking damage a year per $1,000, Ajax is about even with the typical $0.030 (1.4 times).
Shaking damage a year per $1,000 of building value
Neither high nor low in Ontario: Ajax’s $0.042 sits by the median of $0.043, while Alexandria reaches $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.
Ajax sits mid-range among Canada’s 2,611 towns: 43% 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).
Only shaking damage to buildings in Ajax is counted; landslides, liquefaction, tsunami and fire after a quake aren’t.
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 Ajax: 0% of area homes over the guideline
Health Canada’s survey of long-term home tests: the share above the 200 Bq/m³ guideline.
At 0% over the guideline, the area around Ajax is under the typical Canadian town’s 6.6%. For radon tests, the only official count covers all of the Durham Regional Health Unit, Ajax included.
Tested homes over 200 Bq/m³
Over 600 Bq/m³
Fewer homes top the guideline around Ajax (0%) than in the typical town in Ontario (4%).
Health Canada radon survey (2009–2011), by 2007 health region; medians of towns of 2,500 people or more.
Radon rarely tops the guideline around Ajax, as for 37% of Canada’s 2,611 towns; 63% see more.
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.
Neighbouring homes in Ajax can differ a lot; only a long-term test tells you about yours.
Health Canada, Cross-Canada Survey of Radon Concentrations in Homes (2009–2011).
Where to get warnings in Ajax
Environment and Climate Change Canada issues the weather alerts for Ajax; 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 Ajax, and listen to local authorities for orders.
Weather alerts (ECCC) · Alert Ready · Fire danger and active fires (CWFIS)
Hazards in the places around Ajax
The same four hazards for the places next door.
| Town | Wildfire | Quake $/1,000 | Radon | Flood study |
|---|---|---|---|---|
| Ajax | Low | $0.042 | 0% | Yes |
| Pickering 118,378 · 6.6 km | Low | $0.031 | 0% | Yes |
| Whitby 162,413 · 8.5 km | Low | $0.036 | 0% | Yes |
| West Rouge 20,915 · 12 km | Low | $0.043 | 2.7% | Yes |
| Centennial Scarborough 13,453 · 13 km | Low | $0.043 | 2.7% | Yes |
| Highland Creek 12,678 · 14 km | Low | $0.043 | 2.7% | Yes |
| Oshawa 213,592 · 15 km | Low | $0.033 | 0% | Yes |
Fire is no heavier anywhere nearby than around Ajax (low), with Whitby next at low.
Radon is the survey area’s figure, so neighbours in one area share it.
Get ready for what Ajax faces
What to do about the hazards Ajax 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.
- Clear needles and wood nearby.
- Keep a grab-and-go bag ready.
- In smoke, stay in; filter air.
- Has it had a radon test?
- Check the address on the flood map.
- Are flood and wildfire insured?
What this data can and can’t tell you
- Radon is a survey. Health Canada’s survey tested some 14,000 homes over three months; until postal-area boundaries are loaded, Ajax takes its 2007 health region’s share.
- Wildfire counts one way. For Ajax, wildfire means how much nearby land burned in the past forty years, a one-way input that can pull Risk down and nothing more.
- Earthquakes are modelled. Seismic risk is NRCan’s model of yearly building losses from shaking, averaged over many years and given for Ajax’s census subdivision (a neighbourhood shows its city’s).
- 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 Ajax.
Questions about flooding and hazards in Ajax
Is Ajax at risk of wildfire?
Less than most of Canada: 0% of the land within 25 km of Ajax has burned since 1986, the last in 2001, a low band that leaves Risk alone.
How big is the earthquake risk in Ajax?
About $0.042 a year per $1,000 of building value, NRCan’s long-run expectation for Ajax.
How is Ajax’s Hazard risk Grade worked out?
Ajax grades A for hazard risk, from earthquakes and radon, with wildfire counted only where it lowers the grade.
Is radon a problem in Ajax?
In Health Canada’s survey, 0% of 95 homes tested in Ajax’s area were above 200 Bq/m³, though only a test tells you about one house.
Does Ajax flood?
The inventory lists a study touching Ajax; 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).