Ossifrage
Isn't a thinner weaker more mobile pack more prone to piling up and ridging when pushed into an obstacle. Its one partial negative feedback I occasionally ponder - ice thickens fastest when thin, so if new ice is continually pushed aside faster than in the past , the rate of new winter ice creation will be higher(provided the extra energy released can successfully escape to space). If the winds push that ice in the right direction, its a way the system can replenish itself somewaht after a bad season.
Those stamukha anchors explain the scour marks in the ESS discussed at length here earlier I think
(But lets not derail the thread, back to weather forecasts for me!)
I'll give a caveat that the mechanics of this process haven't been studied in a great deal of depth. I'm not sure that anyone has ever meaningfully revised Parmeter and Coon's model of pressure ridge formation, and that dates back to 1972!
But the short answer is no, thinner ice doesn't make better pressure ridges. Thicker, stronger ice subjected to loading forces sheared into relatively large blocks that allow (well ... increasingly, allow
ed) for greater value as structural elements. Thinner ice does not have the tensile strength to respond in this manner and instead crumbles or crumples at floe boundaries; indeed, we've all watched image progressions that show large floes making contact and breaking apart rather than conglomerating. Even to the extent that thinner, weaker ice can form traditional pressure ridges, they are limited to smaller "masts" and (presumably) correspondingly shallower "keels".
Ice does thicken fastest when thin, and there are ridging processes that play a part in that, but their physical mechanics are very different than those of traditional MYI pressure ridges. It's not a negative feedback mechanism.
Back to the condition of current ice, there's enough clearing of the cloud deck to get the first good update for the Sverdrup Islands area in several days, and the CAA/CAB crack is really taking its toll. Fast ice on the east shore of Borden Island has retreated some 20 km since the 19th, and there is clear -- if less pronounced -- ice loss across the northern boundary of the Prince Gustav Adolf Sea.
At the primary southern outlet of the PGAS, the Maclean Strait, the situation is more dire. This area has been under cloud for quite awhile, although as recently as the 18th-19th, what little was visible under the clouds seemed to be largely holding intact. That's no longer the case. Ice in the Maclean visibly cracked on (or before) the 22nd, and clear skies on the 23rd show the entire triangle between Loughead, King Christian, and Bathurst has shattered completely. In 2012, this area saw considerable melting. Even if this region doesn't melt enough to show on the top-line metrics, the speed at which its quality has degraded is concerning; that's especially true because increased motility in the Maclean allows it to act as an export channel for ice from the PGAS.
Further east, a large (~10km) floe has separated from fast ice immediately to the west of Meighan Island. This isn't likely to melt immediately; there's a 20+ km floe northeast of Meighan that's just been hanging out for awhile now. But
that floe originated with the breakup of CAB sea ice north of Axel Heiberg in late May and has drifted over 150 km since. The rate and direction of floe movement is in part weather dependent (but also will tend to increase, to some limit, as the ice becomes more free to move). But if we use the last two months as a rough benchmark, both of these floes could make it nearly to Ellef Ringnes before the end of the season. In turn, that suggests why the Beaufort has seemed so resistant to clearing this year; it is being supplied with ice from the CAA/CAB boundary at a prodigious rate, some of which represents the remaining MYI stores in that region. In effect, the "crack" is dumping large volumes of typically-protected ice into the Beaufort. Even if quite a bit survives this season, it isn't where it needs to be long term.
The melt pressure on the CAA from the north is perhaps unprecedented. Damage is being done, even if extent and area don't take hits.