Photo: James Abbott from New Westminster, B.C., Canada · CC BY-SA 2.0Earthquake risk in Cowichan Bay runs 36 times the typical Canadian town’s: $1.08 per $1,000 a year
Wildfire is rare near Cowichan Bay: 0.1% of the land within 25 km has burned since 1986, a burn rate of 0.003% a year. Fewer homes than usual carry radon here, 0.9% over the guideline where the typical town has 6.6%. Hazard risk gives Cowichan Bay a grade of B−; its wildfire band pulls it down.
What stands out about Cowichan Bay’s hazards
For Cowichan Bay, from NRCan’s seismic model, Health Canada’s radon survey, the national burned-area record and the flood map inventory.
What Cowichan Bay faces
Each hazard against its own yardstick; meters run from low to high on that yardstick.
Wildfire
Earthquakes
Radon
Flood study
Hazard risk in Cowichan Bay: B−
Seismic risk and radon set Cowichan Bay’s grade, wildfire can drag it down, and flood mapping stays out of it.
Its place: #167 of 254 in British Columbia and #1,704 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 Cowichan Bay: 0.1% of the land within 25 km burned since 1986, 0% within 5 km
Past fire around Cowichan Bay’s homes, from the national burned-area record, with the fuel within 5 km.
In a typical year 0.003% of the land near Cowichan Bay burns; the typical Canadian town sees 0.000%, and both are low.
The 5 km ring around Cowichan Bay’s homes is clear of burns since 1986, the nearest 7.1 km out.
Forest fuel covers 38% of the land close to Cowichan Bay and 75% 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
In the lower half in British Columbia: Cowichan Bay at 0.003% a year, 191st of 255, far from Oliver’s 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.
7.5% of Canada’s 2,610 towns burn fast enough to rank moderate or above; Cowichan Bay 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.
Cowichan Bay is on the flood map inventory: 4 studies, latest by Cowichan Valley Regional District
What Canada’s Flood Map Inventory lists for Cowichan Bay: who studied flooding and where to see their maps.
The newest of 4 studies covering Cowichan Bay is Cowichan Valley Regional District’s, from 2022; open its map to see the zones.
| Study | By | Year | Status |
|---|---|---|---|
| Chemainus River Flood Mapping Program Part 1 Flood Mapping | Cowichan Valley Regional District | 2022 | final |
| Lower Cowichan/Koksilah River Integrated Flood Management Plan | Cowichan Valley Regional District | 2009 | final |
| Cowichan and Koksilah Rivers at Duncan Floodplain Mapping | Ministry of Environment and Climate Change Strategy | 1997 | final |
| Chemainus River Floodplain Mapping (including Bonsall Creek) | Ministry of Environment and Climate Change Strategy | 1991 | final |
Towns with a flood study on file
Cowichan Bay 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.
Mapping around Cowichan Bay began in the 1990s; the 1990s saw the most work (2 of 4 studies), the latest in the 2020s.
Study dates as the NRCan inventory lists them, one count per study touching Cowichan Bay.
Listed, not scored: a flood study proves a map exists, not that Cowichan Bay floods.
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.
Shaking is Cowichan Bay’s costliest hazard: $1.08 a year per $1,000
Expected yearly building losses from earthquakes, from Natural Resources Canada’s model.
Roughly 35.9 times the typical $0.030: Cowichan Bay’s $1.08 marks real seismic exposure.
Shaking damage a year per $1,000 of building value
Earthquake risk in British Columbia peaks in Duncan ($1.33); Cowichan Bay, at $1.08, sits above the median of $0.36.
NRCan seismic risk model (2022): mean yearly building loss per $1,000 of value; medians of towns of 2,500 people or more.
Only 0.1% of Canada’s 2,611 towns expect more shaking damage than Cowichan Bay.
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 Cowichan Bay 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 Cowichan Bay: 0.9% of area homes over the guideline
Long-term radon tests in homes across the survey area, against Health Canada’s guideline.
At 0.9% over the guideline, the area around Cowichan Bay is under the typical Canadian town’s 6.6%. For radon tests, the only official count covers all of the Central Vancouver Island health region, Cowichan Bay included.
Tested homes over 200 Bq/m³
Over 600 Bq/m³
Against the typical town in British Columbia (1.8%), the area around Cowichan Bay has fewer high tests: 0.9%.
Health Canada radon survey (2009–2011), by 2007 health region; medians of towns of 2,500 people or more.
Under 5% puts Cowichan Bay 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.
Neighbouring homes in Cowichan Bay 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 Cowichan Bay
Alerts for Cowichan Bay 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 Cowichan Bay to phones; CWFIS shows the day’s fire danger.
Weather alerts (ECCC) · Alert Ready · Fire danger and active fires (CWFIS)
How Cowichan Bay’s neighbours compare on hazards
Wildfire band, earthquake risk, radon and flood studies for each place nearby.
| Town | Wildfire | Quake $/1,000 | Radon | Flood study |
|---|---|---|---|---|
| Cowichan Bay | Low | $1.08 | 0.9% | Yes |
| Cobble Hill 5,074 · 5.6 km | Low | $0.68 | 0.9% | None listed |
| Cowichan 2,509 · 6.4 km | Low | $0.72 | 0.9% | Yes |
| Electoral Area E, Cowichan Valley 4,482 · 7.3 km | Low | $0.83 | 0.9% | Yes |
| Duncan 5,745 · 7.8 km | Low | $1.33 | 0.9% | Yes |
| Shawnigan 9,903 · 9.6 km | Low | $0.57 | 0.9% | Yes |
| North Cowichan 34,525 · 10 km | Low | $0.76 | 0.9% | Yes |
The fire record around Shawnigan is a touch heavier than Cowichan Bay’s, but the band is the same: low (here low).
Radon is the survey area’s figure, so neighbours in one area share it.
Get ready for what Cowichan Bay faces
Practical steps for Cowichan Bay’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.
- 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
- Radon is a survey. About 14,000 homes were tested across Canada in 2009–2011, and the share over the guideline for Cowichan Bay is its health region’s, the survey’s design unit.
- Wildfire counts one way. For Cowichan Bay, 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 Cowichan Bay’s census subdivision (a neighbourhood shows its city’s).
- 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 Cowichan Bay.
Questions about flooding and hazards in Cowichan Bay
Is radon a problem in Cowichan Bay?
The area’s survey found 0.9% of 109 tested homes above Health Canada’s guideline, so a three-month test is worth doing in Cowichan Bay.
Is Cowichan Bay at risk of wildfire?
Some, but Cowichan Bay’s low band (0.1% of nearby land burned since 1986, latest 2022) is short of the level that counts.
Does Cowichan Bay flood?
There is flood mapping for Cowichan Bay on the national inventory, each study linked to its owner’s map, none of them graded.
How is Cowichan Bay’s Hazard risk Grade worked out?
Hazard risk gives Cowichan Bay B−, weighing earthquakes and radon and counting wildfire only against it.
How big is the earthquake risk in Cowichan Bay?
In NRCan’s seismic model, Cowichan Bay’s buildings lose $1.08 per $1,000 of value in an average year.
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).