09 June 2004

Joined: 23 Mar 2004 Posts: 87

June 9, 2004 Wednesday
9:00 PM Alaska time

We are in the Beaufort Sea, east of Barrow, AK. I never imagined ice could have so many different appearances. The floe I walked on June 4th was rather flat with a few, tiny pressure ridges. The ice we are seeing today has a remarkable amount of rubble and larger ice chunks on it. The disaggregated ice is caused by tremendous amounts of pressure being applied to meeting areas of two or more floes. The action is similar to plate tectonic convergence seen in the Himalayan mountains. When the floes meet, uplifting occurs resulting in pressure ridges. There are so many pressure ridges here that it looks like rubble. Of course, some of the “rubble” is the size of a small car.

Word of the Day: rubble: Fragments of hard sea ice, roughly spherical and up to 5 feet in diameter, resulting from the disintegration of larger ice formations. When afloat, it is commonly called brash ice. Many of the jagged ice chunks around us now are larger than this, closer to 10 feet across which weigh in around 100 tons each. -W. RALL, XO

Sometimes the pressure ridges grow very quickly. Earlier this morning the bridge saw one ridge grow directly in the path of the Healy’s bow in 5 minutes. Sometimes they take longer. Susan Schonberg filmed a ridge forming this afternoon for about a half hour.

As pressure forced two ice floes together, one floe began to ride on top of the other. Picture by Susan Schonberg.

The floe continued to rise throughout the day. Notice the slightly higher angle of the ice and the growing space below. Also notice the ice chunk falling from the slab, adding to the rubble field. Picture by Susan Schonberg.