These subtle ripples have revealed the presence of thousands of previously unknown hills, valleys, ridges and ancient river systems. New paper in Science Magazine from Helen Ockenden et al. www.science.org/doi/10.1126/...

I haven't heard about the disagreements. The ice was sitting on an ice plain - a very flat bed with low basal drag. These are present beneath the downstream parts of many Antarctic glaciers where the sediment they transport has built a depositional body known as a grounding zone wedge.

And if you want a longer read, my old mate Mark Poynting has a great write-up on Auntie Beeb. www.bbc.co.uk/news/article...

"Such records are vital for distinguishing between rapid grounding-line retreat, as is reported to have occurred at Hektoria Glacier, versus the retreat of a floating ice margin through “conventional” iceberg calving processes," says polar SAR specialist Frazer Christie at Airbus Defence and Space.

But the paper has caused a stir because there is wide disagreement in the glaciology community about precisely where Hektoria had been fully grounded on bedrock due to a lack of high-accuracy satellite records.

Swansea Uni co-author @adrianluckman.bsky.social put this Sentinel-1 movie together. "Although the paleo record indicates some very rapid retreats in the past, the pace of retreat of Hektoria Glacier and its neighbours is unprecedented in the observational record," Adrian says.

Ochwat and Colorado/Boulder co-author Ted Scambos described the lightning-fast fracturing as “shocking” and warned that the retreat “changes what’s possible” for important glaciers elsewhere on the continent. www.nature.com/articles/s41...

Hektoria lost ~25km in 15 months, with 8.2km fragmenting in just the Nov/Dec of 2022. Naomi Ochwat et al point to a particular vulnerability: an "ice plain" - a big section of glacier ice sitting on flat seabed rock that suddenly goes afloat, spitting off icebergs like crazy.

OK, the US National Ice Center was being a bit more generous than me. It logged A23a at 2,371 sq km. For comparison, the current title holder of the "world's biggest iceberg" is A15a at 3,070 sq km, grounded in the Amery Sea off East Antarctica.

Iceberg D15a, grounded in the Amery Sea, is now officially "the world's biggest iceberg".