Yukon: Design Values and Geology
The page that comes before the calculator, Yukon edition: gold country that the ice sheets missed, permafrost that the climate is now renegotiating, and the highest mountain in Canada standing over the most seismically active corner of the territory.
| Land area | about 482000 km2 |
| Highest point | Mount Logan, 5959 m, the highest in Canada |
| Permafrost | discontinuous under most of the territory, continuous in the north, and thawing where disturbed or warming |
| Foundations, typical answers | granular pads, piles, and thermosyphons where the ground must stay frozen |
| Ground snow load, representative | roughly 2 kPa in the southern valleys, more in the mountains, with drifting in open country |
| January design temperature | the low −40s in the interior valleys, colder at Old Crow |
| Heating degree days | roughly 6800 at Whitehorse and rising northward |
| Seismic character | elevated in the southwest, where the St Elias and Denali fault systems are among the most active in Canada |
| The signature deposit | Klondike placer gold, preserved because the ice sheets never crossed it |
| Logistics | one highway spine, long hauls, and winter as the working season for some ground |
The geology in brief
| Klondike and central plateaus | unglaciated Beringia, deep weathered gravels and the placer fields of 1896 |
| Yukon Tanana terrane | the metamorphic heart of the territory and its lode gold camps |
| St Elias Mountains, southwest | Logan and the icefields, along the most active faults in the north |
| Tintina Trench | the great strike slip valley that organizes the territory’s geography |
| The north | continuous permafrost toward the Beaufort coast |
Much of the Yukon belongs to Beringia, the country the ice sheets went around, which is why the Klondike still had its ancient weathered gravels and their gold when prospectors arrived in 1896: nothing had bulldozed them into the sea. The bedrock beneath is Cordilleran terrane country, and the southwest corner is where the accretion is still violent: the St Elias and Denali fault systems generate the territory’s real earthquakes, with the 2002 Denali magnitude 7.9 next door in Alaska as the modern reminder.
The other half of the geology is thermal. Permafrost underlies most of the territory in discontinuous fashion, thickest and coldest in the north, patchy and warm in the south, and warm permafrost is the treacherous kind: a degree of change or a stripped moss layer converts frozen bearing into thawing mud. Dawson City’s leaning heritage buildings are the territory’s open air textbook on the subject.
What the ground means for construction
Foundation design starts with a thermal question before a structural one: keep the ground frozen, or get through the frozen zone entirely. Granular pads preserve the thermal regime under light structures, piles carry serious loads, thermosyphons buy certainty where the ground is warm, and site clearing is treated as the geotechnical act it is, since the organic mat is the insulation holding everything together.
The Alaska Highway is the territory’s running case study: sections built over ice rich ground have been settling and being rebuilt for eighty years, and a warming climate is accelerating the file. Add southwest seismicity to structures near the St Elias front, drifting snow in open country, and logistics where the highway is singular and the sealift does not reach, and remoteness becomes a design load with a unit price.
Design values to verify
The ranges on this page are representative planning figures assembled from public climate records and common practice. They are deliberately not code tables. Site specific climatic design data lives in the National Building Code Appendix C, municipal bylaws set frost depths, and seismic values for a coordinate come from the national hazard calculator. Plan with the ranges, design with the code, and when the two disagree, the code wins.
Official sources
- Government of Yukon: the Yukon Geological Survey and territorial standards.
- Environment and Climate Change Canada: climate normals and extremes behind the ranges above.
- Earthquakes Canada: site specific hazard, elevated in the southwest.
Related Calculators and Reference
- Pile Bearing Capacity Estimator: the workhorse where the ground must be bypassed.
- Presumptive Bearing Capacity Values: with the caveat that frozen ground rewrites the table.
- Load Combination Generator: snow, wind and drift into combinations.
- Proctor Compaction Test: behind every granular pad specification.
- British Columbia: Design Values and Geology: the neighbouring page in this series.