Photo: Joe Mabel (on Flickr as Joe Mabel from Seattle, US) · CC BY-SA 3.0Few places are as safe from hazards as Whitby: it beats 88% of Canadian towns
Wildfire isn’t Whitby’s worry: 0% of the land within 25 km burned since 1986 (0.001% a year). Seismic risk in Whitby sits near the middle: $0.036 of expected damage per $1,000 of buildings a year, the typical town $0.030. Fewer homes than usual carry radon here, 0% over the guideline where the typical town has 6.6%. Hazard risk gives Whitby a grade of A; its wildfire band pulls it down.
What stands out about Whitby’s hazards
Four national sources, each read for Whitby: earthquakes, radon, past fires and flood studies.
What Whitby faces
Each hazard against its own yardstick; meters run from low to high on that yardstick.
Wildfire
Earthquakes
Radon
Flood study
Whitby grades A for hazard risk
Two inputs always count for Whitby, earthquakes and radon; the third, wildfire, counts only against a town.
Its place: #189 of 866 in Ontario and #510 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.
Wildfire is rare near Whitby: 0% of the land within 25 km burned since 1986, 0% within 5 km
Past fire around Whitby’s homes, from the national burned-area record, with the fuel within 5 km.
Low: the land around Whitby burns at 0.001% a year, where the typical Canadian town sees 0.000%.
Since 1986 the nearest fire to Whitby’s homes came within 14 km, never inside 5 km.
Forest fuel is spread evenly around Whitby: 8.4% within 5 km, 13% 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
The land around Whitby burns at 0.001% a year, the 83rd highest rate of 871 towns in Ontario; Sioux Lookout tops it 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 takes in 92% of Canada’s 2,610 towns, Whitby among them, though its rate is above zero; 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 Whitby is mapped in 5 studies, the newest by Central Lake Ontario Conservation Authority
What Canada’s Flood Map Inventory lists for Whitby: who studied flooding and where to see their maps.
Central Lake Ontario Conservation Authority and others have studied flooding in areas that include Whitby: 5 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 |
| Corbett Creek Master Drainage Plan | Central Lake Ontario Conservation Authority | 2021 | final |
| Pringle Creek Master Drainage Plan Update | Central Lake Ontario Conservation Authority | 2018 | final · not public |
Towns with a flood study on file
Flood maps are common in Ontario: 69% of towns have one, against 58% nationally, and Whitby is among them.
NRCan Canada Flood Map Inventory: a study footprint touching the town’s boundary; towns of 2,500 people or more.
Mapping around Whitby goes back to the 2010s and peaks in the 2020s, with 4 of its 5 studies.
Study dates as the NRCan inventory lists them, one count per study touching Whitby.
The grade leaves flood out, since a study area says nothing about how many of Whitby’s homes are at risk.
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.
Ordinary seismic risk in Whitby: $0.036 per $1,000 of buildings a year
Expected yearly building losses from earthquakes, from Natural Resources Canada’s model.
Nothing unusual about Whitby’s ground: $0.036 against a typical $0.030, 1.2 times.
Shaking damage a year per $1,000 of building value
Shaking damage around Whitby runs at $0.036 a year, near the $0.043 of the typical town in Ontario; Alexandria has $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.
Middle of the pack: 46% of Canada’s 2,611 towns have more earthquake risk than Whitby.
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 Whitby’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 low around Whitby: 0% of tested homes over the guideline
Long-term radon tests in homes across the survey area, against Health Canada’s guideline. · Area-wide: radon tests, counted over the Durham Regional Health Unit
A lower share than most: 0% of tested homes around Whitby, the typical Canadian town 6.6%.
Tested homes over 200 Bq/m³
Over 600 Bq/m³
Fewer homes top the guideline around Whitby (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.
Whitby is in the lowest band, with 37% of Canada’s 2,611 towns: under 5% of tests over the guideline, while 63% have 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.
One home in Whitby can be high while next door is low; a three-month test settles it.
Health Canada, Cross-Canada Survey of Radon Concentrations in Homes (2009–2011).
Weather and fire alerts for Whitby
Environment and Climate Change Canada issues the weather alerts for Whitby; 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 Whitby, and listen to local authorities for orders.
Weather alerts (ECCC) · Alert Ready · Fire danger and active fires (CWFIS)
Hazards in the places around Whitby
Wildfire band, earthquake risk, radon and flood studies for each place nearby.
Fire is no heavier anywhere nearby than around Whitby (low), with Oshawa next at low.
Radon is the survey area’s figure, so neighbours in one area share it.
Get ready for what Whitby faces
What to do about the hazards Whitby 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
- Wildfire counts one way. Wildfire is read from the national burned-area record around Whitby’s homes since 1986, a history of fire that may lower Risk but never raises it.
- Flood studies aren’t flood zones. Flood studies cover areas of every size, which is why the page lists them for Whitby without grading them.
- Earthquakes are modelled. NRCan models what earthquakes would cost buildings each year on average, subdivision by subdivision; Whitby’s figure is its subdivision’s.
- 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 Whitby until then.
Questions about flooding and hazards in Whitby
Is radon a problem in Whitby?
Around Whitby, 95 survey homes were tested and 0% came in over 200 Bq/m³, a guide to the area, not to any one home.
How big is the earthquake risk in Whitby?
NRCan’s model expects shaking to cost buildings in Whitby $0.036 a year for every $1,000 of their value, on average over many years.
How is Whitby’s Hazard risk Grade worked out?
Whitby’s Hazard risk grade is A, built on earthquakes and radon with a one-sided wildfire input.
Is Whitby at risk of wildfire?
Fire has reached 0% of the land around Whitby since 1986 (last in 2001); at low, it neither helps nor hurts the grade.
Does Whitby flood?
A flood study covers Whitby on Canada’s Flood Map Inventory; open the owner’s map to check a street, since flood isn’t graded.
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).