[1] Univ Montreal, Dept Geog, 520 Chemin Cote St Catherine, Montreal, PQ H2V 2B8, Canada
[2] Univ Montreal, Ctr Etud Nord, 520 Chemin Cote St Catherine, Montreal, PQ H2V 2B8, Canada
[3] Univ Lethbridge, Dept Geog, Lethbridge, AB T1K 3M4, Canada
[4] Univ Wisconsin, Dept Atmospher & Ocean Sci, Madison, WI 53706 USA
[5] Swansea Univ, Dept Geog, Singleton Pk, Swansea SA2 8PP, W Glam, Wales
[6] Wilfrid Laurier Univ, Cold Reg Res Ctr, Waterloo, ON N2L 3C5, Canada