Structure of a Multi-Year Pressure Ridge

• Published in: ARCTIC
• Main Authors: Kovacs, A., Weeks, W.F., Ackley, S., Hibler, W.D.
• Format: Article in Journal/Newspaper
• Language: English
• Published: The Arctic Institute of North America 1973
• Subjects: Icebreakers; Icebreaking; Marine transportation; Physical properties; Pressure ridges; Salinity; Sea ice; Manhattan (Ship); Strength; Beaufort Sea; Arctic
• Online Access: https://journalhosting.ucalgary.ca/index.php/arctic/article/view/65945

Three transverse profiles across a large pressure ridge located in the Beaufort Sea are presented. The ridge sail extended 4m. above sea level and the ridge keel 13 m. below. The cross-sections of the ridge keel can be described as roughly semi-circular. This suggests that form drag coefficients for flow transverse to the long axes of multi-year ridges may be as high as 0.8. Examination of several salinity, temperature and brine-volume profiles shows that much of the ice in the ridge has a very low salinity and is quite strong. All the inter-block voids that initially existed in the ridge at the time of its formation have been completely filled with ice. These observations, coupled with icebreaking experience indicate that multi-year ridges are, indeed, significant obstacles to even the largest icebreaking ship and should be avoided if possible. A very large first year ridge with a sail height of 12.8 m. is also described. This is the largest free-floating ridge yet measured.