Winter Sub-Freezing Periods and Significant Thaws in the Boreal Forest Region of Central North America

• Main Authors: Thomas W. Schmidlin, Rebecca A. Roethlisbergeri
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 1992
• Subjects: Key words; winter; freezing temperature; boreal forest; Canada; Great Lakes; Arctic
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.485.9895; http://pubs.aina.ucalgary.ca/arctic/Arctic46-4-359.pdf

Minnesota over the period 1960-88. The longest sub-freezing period of winter averaged 20-30 days in the southern portion of the region, 30-40 days around Lake Superior, and 90-100 days in extreme northwestern Ontario. These are twice as long as sub-freezing periods at similar latitudes in eastern Canada. The sub-freezing period is shortened by about one week along the shores of the Great Lakes. There is annual spatial correlation of the longest sub-freezing period, indicating regional synoptic-scale control. The late 1970s had the longest sub-freezing periods but no significant linear trend was found in lengths of sub-freezing periods. The average date of the first significant thaw (> 10°C) ranged from early March in the south to late April in the north and is delayed 1-2 weeks along the shores of the Great Lakes.