Wind as a Geomorphic Agent in Cold Climates

The final major section (Chapters 11-15) deals with wind effects on snow cover. After a review of snow and its properties, successive chapters cover drift of snow, snow accumulation and its geomorphic effects, deflation of snow cover, and the effects of wind-packed or deflated snow on ground freezing and on resulting hummocks, palsas, and other frozen-ground features. Although snow avalanches are mentioned in passing, the role of wind in loading avalanche-prone slopes, forming wind-slab detachment surfaces, and building cornices that may collapse to trigger avalanches is largely ignored. A vast literature deals with these destructive events, which generally cause 50 or more deaths annually in the United States and Canada alone. Topics that could well have been covered in this volume include (1) geomorphic and botanic indicators of avalanche tracks and runout zones, (2) meteorologic conditions conducive to avalanches, (3) prediction of avalanche runout distances, and (4) determination of avalanche recurrence intervals. Slush flows (p. 276-278) receive more systematic coverage, but further information and illustrations could have been provided on recognition criteria for these hazardous high-latitude and alpine events.