Photo: Sidney Museum · CC BY-SA 3.0Sidney has one of Canada’s highest earthquake risks: $0.76 a year per $1,000, 25 times the typical town’s
Around Sidney, wildfire is practically absent from the record: 0% within 25 km since 1986, 0.001% a year. Radon is lower than usual: 1.8% of tested homes in the survey area topped the guideline, against 6.6% for the typical town. Sidney grades C+ for hazard risk; wildfire is low here, so it earns no credit.
What stands out about Sidney’s hazards
Four national sources, each read for Sidney: earthquakes, radon, past fires and flood studies.
What Sidney faces
Each hazard against its own yardstick; meters run from low to high on that yardstick.
Wildfire
Earthquakes
Radon
Flood study
Hazard risk in Sidney: C+
The grade weighs Sidney’s seismic risk and radon equally, and wildfire is one-sided: a high band counts against a town, a low one earns nothing.
Its place: #187 of 254 in British Columbia and #1,805 of 2,589 Canadian towns.
How sure: Earthquake losses are a model’s expectation over many years, not a forecast for any one. Only 55 homes were tested in the survey area, so the radon share is rough. Small fires and grass fires are largely missing from the national burned-area record.
Few fires near Sidney: 0% within 5 km, 0% within 25 km
Past fire around Sidney’s homes, from the national burned-area record, with the fuel within 5 km.
Around Sidney fire takes 0.001% of the land in a typical year, the typical Canadian town 0.000%, which is low.
The closest burn since 1986 lies 9.5 km from Sidney’s homes, none within 5 km.
Forest fuel covers 34% of the land close to Sidney and 66% across 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 British Columbia · highest of 255
Sidney ranks 239th of the 255 towns in British Columbia for burn rate (0.001% a year), in the lower half; Oliver leads at 0.98%.
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, Sidney 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.
A flood study covers Sidney, from Capital Regional District: 1 on the inventory
What Canada’s Flood Map Inventory lists for Sidney: who studied flooding and where to see their maps.
The flood study touching Sidney is Capital Regional District’s, dated 2021; its own map shows the zones street by street.
| Study | By | Year | Status |
|---|---|---|---|
| Capital Regional Coastal Flood Inundation Mapping Project | Capital Regional District | 2021 | final |
Towns with a flood study on file
Sidney is one of the 76% of towns in British Columbia with a flood study on file; across Canada it is 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 Sidney’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.
High seismic risk in Sidney: $0.76 per $1,000 of buildings a year
Expected yearly building losses from earthquakes, from Natural Resources Canada’s model.
At $0.76 per $1,000, Sidney carries roughly 25.4 times the typical Canadian town’s earthquake risk ($0.030).
Shaking damage a year per $1,000 of building value
Above the middle in British Columbia: Sidney’s $0.76 against a median of $0.36, with Duncan highest at $1.33.
NRCan seismic risk model (2022): mean yearly building loss per $1,000 of value; medians of towns of 2,500 people or more.
Few of Canada’s 2,611 towns face more earthquake damage than Sidney: 0.3% of them.
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 Sidney’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).
Little radon around Sidney: 1.8% of area homes over the guideline
Long-term radon tests in homes across the survey area, against Health Canada’s guideline.
Radon runs below the typical Canadian town (6.6%) in Sidney’s area, at 1.8%.
Tested homes over 200 Bq/m³
Over 600 Bq/m³
Around Sidney, 1.8% of tests topped the guideline, about the same as the typical town in British Columbia (1.8%).
Health Canada radon survey (2009–2011), by 2007 health region; medians of towns of 2,500 people or more.
The quietest radon band, under 5%, holds 37% of Canada’s 2,611 towns and Sidney; 63% 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.
The share describes the area, not a house: in Sidney as anywhere, test to be sure.
Health Canada, Cross-Canada Survey of Radon Concentrations in Homes (2009–2011). · Area behind the radon tests figures: the South Vancouver Island health region
Weather and fire alerts for Sidney
Environment and Climate Change Canada issues the weather alerts for Sidney; 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. |
Smoke and fire warnings for Sidney come through Environment Canada and Alert Ready; the fire map is CWFIS’s.
Weather alerts (ECCC) · Alert Ready · Fire danger and active fires (CWFIS)
Hazards in the places around Sidney
Wildfire band, earthquake risk, radon and flood studies for each place nearby.
| Town | Wildfire | Quake $/1,000 | Radon | Flood study |
|---|---|---|---|---|
| Sidney | Low | $0.76 | 1.8% | Yes |
| North Saanich 12,986 · 2.4 km | Low | $0.73 | 1.8% | Yes |
| East Saanich 2 1,962 · 7.4 km | Low | $0.81 | 1.8% | Yes |
| Central Saanich 18,184 · 9.4 km | Low | $0.86 | 1.8% | Yes |
| Electoral Area A, Cowichan Valley 5,156 · 11 km | Low | $0.75 | 0.9% | Yes |
| Cobble Hill 5,074 · 13 km | Low | $0.68 | 0.9% | None listed |
| Highlands 2,753 · 15 km | Low | $0.37 | 1.8% | Yes |
Highlands burns a little more than Sidney, in the same low band (low here).
Radon is the survey area’s figure, so neighbours in one area share it.
Get ready for what Sidney faces
What to do about the hazards Sidney 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?
- 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
- Earthquakes are modelled. NRCan models what earthquakes would cost buildings each year on average, subdivision by subdivision; Sidney’s figure is its subdivision’s.
- Radon is a survey. Health Canada’s survey tested some 14,000 homes over three months; until postal-area boundaries are loaded, Sidney takes its 2007 health region’s share.
- Wildfire counts one way. Wildfire is read from the national burned-area record around Sidney’s homes since 1986, a history of fire that may lower Risk but never raises it.
- 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 Sidney.
Questions about flooding and hazards in Sidney
How big is the earthquake risk in Sidney?
In NRCan’s seismic model, Sidney’s buildings lose $0.76 per $1,000 of value in an average year.
Is radon a problem in Sidney?
In Health Canada’s survey, 1.8% of 55 homes tested in Sidney’s area were above 200 Bq/m³, though only a test tells you about one house.
Is Sidney at risk of wildfire?
Less than most of Canada: 0% of the land within 25 km of Sidney has burned since 1986, the last in 2020, a low band that leaves Risk alone.
Does Sidney flood?
The inventory lists a study touching Sidney; whether a given street floods is on that map, not in the grade.
How is Sidney’s Hazard risk Grade worked out?
Hazard risk gives Sidney C+, weighing earthquakes and radon and counting wildfire only against it.
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).