Photo: Syd Cannings · CC BY 4.0Hazard risk in Macpherson-Grizzly Valley is higher than in 93% of Canadian towns
Some 2.6% of the land within 25 km of Macpherson-Grizzly Valley has burned since 1986; at 0.07% a year that is moderate, not high. Seismic risk runs high: $0.12 of expected damage per $1,000 of buildings a year, the typical town $0.030. In Health Canada’s survey, 20% of homes tested in the area exceeded 200 Bq/m³ (6.6% typical). Hazard risk gives Macpherson-Grizzly Valley a grade of D; its wildfire band pulls it down.
What stands out about Macpherson-Grizzly Valley’s hazards
Four national sources, each read for Macpherson-Grizzly Valley: earthquakes, radon, past fires and flood studies.
What Macpherson-Grizzly Valley faces
Each hazard against its own yardstick; meters run from low to high on that yardstick.
Wildfire
Earthquakes
Radon
Flood study
Macpherson-Grizzly Valley grades D for hazard risk
For Macpherson-Grizzly Valley, Risk will be the average of earthquakes and radon, with wildfire added only if it makes the average worse.
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.
A moderate wildfire record for Macpherson-Grizzly Valley: 2.6% within 25 km burned, 0% within 5 km
Past fire around Macpherson-Grizzly Valley’s homes, from the national burned-area record, with the fuel within 5 km.
At 0.07% of the land a year, Macpherson-Grizzly Valley’s burn rate is moderate; the typical Canadian town sees 0.000%.
Since 1986 the nearest fire to Macpherson-Grizzly Valley’s homes came within 7.9 km, never inside 5 km.
There is forest near Macpherson-Grizzly Valley’s homes (70% within 5 km) and more of it further out (79% 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).
Macpherson-Grizzly Valley is in the moderate band, which holds 5.4% of Canada’s 2,610 towns; 2.1% 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.
Macpherson-Grizzly Valley is on the flood map inventory: 1 study, by Government of Yukon, Geomatics Yukon
What Canada’s Flood Map Inventory lists for Macpherson-Grizzly Valley: who studied flooding and where to see their maps.
Government of Yukon, Geomatics Yukon studied flooding in an area that includes Macpherson-Grizzly Valley (2024); open its map to see which streets lie in a flood zone.
| Study | By | Year | Status |
|---|---|---|---|
| Southern Lakes, Yukon (communities of Carcross, Tagish, Marsh Lake, and Lake Laberge) | Government of Yukon, Geomatics Yukon | 2024 | final |
Towns with a flood study on file
Macpherson-Grizzly Valley has a flood study on file, as 58% of Canada’s towns do.
NRCan Canada Flood Map Inventory: a study footprint touching the town’s boundary; towns of 2,500 people or more.
Listed, not scored: a flood study proves a map exists, not that Macpherson-Grizzly Valley 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.
High seismic risk in Macpherson-Grizzly Valley: $0.12 per $1,000 of buildings a year
Expected yearly building losses from earthquakes, from Natural Resources Canada’s model.
Macpherson-Grizzly Valley’s $0.12 is about 3.9 times the typical town’s $0.030: it sits in one of Canada’s more active seismic zones.
Shaking damage a year per $1,000 of building value
With too few towns in Yukon for a median of their own, Macpherson-Grizzly Valley is set beside Canada’s: $0.12 against $0.030.
NRCan seismic risk model (2022): mean yearly building loss per $1,000 of value; medians of towns of 2,500 people or more.
Macpherson-Grizzly Valley sits above most of Canada’s 2,611 towns on earthquake risk; 24% are higher.
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).
Roads, pipes and bridges aren’t in Macpherson-Grizzly Valley’s figure, nor landslides or tsunami: it is buildings and shaking.
Natural Resources Canada, Canada’s Seismic Risk Model (2022), by census subdivision (2016 boundaries; a few 2021 subdivisions take their residents’ mean).
20% of homes tested around Macpherson-Grizzly Valley are over the radon guideline
Long-term radon tests in homes across the survey area, against Health Canada’s guideline.
Macpherson-Grizzly Valley’s survey area reads 20% over the guideline, well past the typical Canadian town’s 6.6%. Macpherson-Grizzly Valley doesn’t get its own radon tests figures; the ones here come from the Yukon Territory health region.
Tested homes over 200 Bq/m³
Over 600 Bq/m³
No median in Yukon to compare with, the territory having too few towns; around Macpherson-Grizzly Valley, 5.8% of tests passed 600 Bq/m³.
Health Canada radon survey (2009–2011), by 2007 health region; medians of towns of 2,500 people or more.
More high tests than most: Macpherson-Grizzly Valley sits in a band that only 22% of Canada’s 2,611 towns share, with 4.6% above.
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 Macpherson-Grizzly Valley 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).
Weather and fire alerts for Macpherson-Grizzly Valley
Alerts for Macpherson-Grizzly Valley 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 Macpherson-Grizzly Valley to phones; CWFIS shows the day’s fire danger.
Weather alerts (ECCC) · Alert Ready · Fire danger and active fires (CWFIS)
Get ready for what Macpherson-Grizzly Valley faces
Practical steps for Macpherson-Grizzly Valley’s hazards, most pressing first.
- Clear needles and wood nearby.
- Keep a grab-and-go bag ready.
- In smoke, stay in; filter air.
- Test for three months in winter.
- Over 200 Bq/m³: fix it.
- Kits are cheap; pros test too.
- 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.
- How close is the forest edge?
- Are flood and wildfire insured?
- Is earthquake cover included?
What this data can and can’t tell you
- Earthquakes are modelled. Shaking damage is modelled from the ground, the buildings and the odds of each quake, and published for whole subdivisions such as Macpherson-Grizzly Valley’s.
- Wildfire counts one way. The wildfire figure is the share of land within 25 km of Macpherson-Grizzly Valley’s homes burned each year from 1986 to 2025, past fire rather than a forecast, and it can only lower Risk.
- Flood studies aren’t flood zones. A study’s area can be a whole watershed or province, so being on the inventory says a map exists, not that a home in Macpherson-Grizzly Valley floods.
- Radon is a survey. The radon share comes from about 14,000 long-term home tests in 2009–2011, pooled for now by the 2007 health region Macpherson-Grizzly Valley sits in.
Questions about flooding and hazards in Macpherson-Grizzly Valley
How big is the earthquake risk in Macpherson-Grizzly Valley?
In NRCan’s seismic model, Macpherson-Grizzly Valley’s buildings lose $0.12 per $1,000 of value in an average year.
Does Macpherson-Grizzly Valley flood?
Macpherson-Grizzly Valley’s area has been studied for flooding, and the owner’s map shows which streets lie in a zone; the grade leaves flood out.
Is Macpherson-Grizzly Valley at risk of wildfire?
Not much by Canadian standards: Macpherson-Grizzly Valley’s band is moderate, with 2.6% of the land within 25 km burned since 1986 (last in 2023), so wildfire doesn’t change its grade.
Is radon a problem in Macpherson-Grizzly Valley?
20% of the 225 homes Health Canada tested around Macpherson-Grizzly Valley topped the guideline; your own house needs its own test.
How is Macpherson-Grizzly Valley’s Hazard risk Grade worked out?
Macpherson-Grizzly Valley grades D for hazard risk, from earthquakes and radon, with wildfire counted only where it lowers 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).