Radiocarbon ages and lichen-dated moraines from 17 glaciers in coastal and nearcoastal British Columbia and Alaska document a widespread glacier advance during the first millennium A.D. Glaciers at several sites began advancing ca. A.D. 200-300 based on radiocarbon-dated overridden forests. The advance is centered on A.D. 400-700, when glaciers along an ϳ2000 km transect of the Pacific North American cordillera overrode forests, impounded lakes, and deposited moraines. The synchroneity of this glacier advance and inferred cooling over a large area suggest a regional climate forcing and, together with other proxy evidence for late Holocene environmental change during the Medieval Warm Period and Little Ice Age, provide support for millennial-scale climate variability in the North Pacific region.

Accelerated glacial recession and downwasting in Pacific North America is exposing land surfaces and features buried by glacial advances that, in many locations, predate the recent Little

The mid-Holocene behaviour of five glaciers in the British Columbia Coast Mountains was reconstructed from radiocarbon ages and stratigraphic analysis. Subfossil wood evidence at Canoe, Fyles, Jacobsen, Tchaikazan and Icemaker glaciers suggests these glaciers were expanding into standing forests prior to 6630, 4900 and 4200 cal. yr BP. Stratigraphically constrained woody detritus at Fyles Glacier records the progradational history of a Gilbert-type delta forming in response to glacial expansion between 7020 and 5470 cal. yr BP. This research provides the first evidence for mid-Holocene glacial expansion in the central and northern British Columbia Coast Mountains. Proxy records describing mid-Holocene climates in the British Columbia Coast Mountains indicate a trend towards slightly cooler and possibly wetter conditions than present. Glacial expansion occurring between 7500 and 4000 cal. yr BP has regional correlatives, suggesting coherent broad-scale climate forcing mechanisms influenced glacial mass balance at this time.

Mass wasting and avalanche events substantially impact the landscape morphology and consequently human habitation throughout the Himalaya. There is, however, a paucity of snow avalanche documentation for the region. The application of dendrochronologic research methods introduces a sensitive approach to document the recurrence of snow avalanche events in a region where historical records are either non-existent or difficult to access. An exploratory dendrochronologic study was undertaken in the Lahul Himalaya of Northern India during the summer of 2006. Included within the fieldwork was an assessment of avalanche track morphology to enable identification of the slope characteristics that might be associated with an increase in avalanche activity. Thirty-six trees growing on the Ratoli avalanche track were sampled. The oldest tree was a Cedrus deodara with a pith date of 1950. A tree-ring-derived avalanche response curve highlights four avalanche events that occurred from 1972 to 2006. The successful scientific results based on the application of the method used provide the basis for local planners to quantify slope failure hazards in forested areas throughout the western Himalaya.