A Permafrost Probability Model for the Southern Yukon and Northern British Columbia, Canada

Permafrost maps are needed for infrastructure planning, climatic change adaptation strategies and northern development but often lack sufficient detail for these purposes. The high‐resolution (30 x 30 m grid cells) probability model for the southern Yukon and northern British Columbia presented in this paper (regional model) is a combination of seven local empirical‐statistical models, each developed from basal temperature of snow measurements in winter and ground‐truthing of frozen‐ground presence in summer. The models were blended using a distance‐decay power approach to generate a map of permafrost probability over an area of almost 500 000 km2 between 59°N and 65°N. The result is broadly similar to previous permafrost maps with an average permafrost probability of 58 per cent for the region as a whole. There are notable differences in detail, however, because the main predictive variable used in the local models is equivalent elevation, which incorporates the effects of gentle or inverted surface lapse rates in the forest zone. Most of the region shows permafrost distribution patterns that are non‐linear, resembling those from continental areas such as Mongolia. Only the southwestern area shows a similar mountain permafrost distribution to that in the European Alps with a well‐defined lower limit and a linear increase in probability with elevation. The results of the modelling can be presented on paper using traditional classifications into permafrost zones but given the level of detail, they will be more useful as an interactive online map. Copyright © 2012 John Wiley & Sons, Ltd.