American Society of Civil Engineers

Alaska Air Temperature Indices—Design ‘Warm’ Winter

by R. L. Scher, P.E., M.ASCE, (Sr. Geotechnical Engineer, R&M Consultants, Inc. 9101 Vanguard Drive, Anchorage, Alaska 99507 E-mail:
Section: Frozen Ground Engineering/General, pp. 700-711, (doi:

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Document type: Conference Proceeding Paper
Part of: Cold Regions Engineering: Cold Regions Impacts on Transportation and Infrastructure
Abstract: Consideration of freezing and thawing air temperatures on foundations, pavements, utilities and structures is integral to civil engineering projects in cold regions. Air-freeze and thaw indices are commonly used to characterize the combined variation, magnitude and duration of annual temperature cycles. Design air temperature indices are typically defined to represent more extreme warm-summer and cold-winter seasons. However, there are situations where a design ‘cold-winter’ freeze index is of little value; e.g. in permafrost regions when the stability and performance of embankments and foundations dependants upon some magnitude of cooling each winter to re-freeze the seasonal active layer and/or lower the subgrade temperature. For these cases it would be more critical to evaluate the thermal consequences of a ‘warm’ winter; e.g. reduced bearing capacity and increased creep. Presented herein are design warm-winter freeze indices, as well as updated cold-winter freeze and warm-summer thaw indices for eleven Alaska communities based on daily climate records from 1971 to 2001 including Anchorage, Barrow, Bethel, Bettles, Central, Fairbanks, Gulkana, Kotzebue, Nome, Northway and Tanana; all but the first located in regions underlain by permafrost.

ASCE Subject Headings:
Freeze and thaw
Temperature effects