Evidence for Climatic Conditions Between CA. 900-1300 A.D. in the Southern Canadian Rockies

Available evidence for climatic conditions in the southern Canadian Rockies around the period of the Early Medieval Warm Period is presented and reviewed. Treelines appear to have been above present levels during the 14th–17th centuries and there is limited evidence of higher treelines ca. 1000 14C yr B.P. (ca. 1000 A.D.). During the 13th century at least three glaciers were advancing over mature forest in valley floor sites, 0.5-1.0 km upvalley of Little Ice Age maximum positions attained in the 18th and 19th centuries. Tree-ring width chronologies from treeline sites show suppressed growth in the early 12th century and for several periods in the 12th–14th centuries. The only tree-ring chronology presently spanning the 900–1300 A.D. interval has generally wider ringwidths between 950 and 1100 A.D. suggesting conditions were more favourable at that time. Forested sites overrun by glaciers in the 12th–14th centuries have only been deglaciated within the present century.