The sea Ice is too heavy for the RRS James Clark Ross to make Rothera base right now. You may have thought the sea ice on the satellite images didn't look too bad, but it's all about how thick the sea ice is, and where the open water is.
To quote the radio officer Mike Gloistein:
The sea-ice around the bottom of Adelaide Island has been heavy and whilst (for those of you who look at the satellite pictures) there are some leads and areas of open water, they are close to land and if we took that route (which also includes shallow water and rocks) and the weather then pushed the ice inland, the ship could easily become stuck between a rock and a hard place.
This was the satellite image I posted yesterday:
And this is a navigation chart of that region.
The light blue shading is shallow water and it's not a great place for a ship to go without freedom of navigation. The sea ice takes away that freedom. This is of course a very sensible choice by the ships Master, and exactly the same thing happened to a voyage I was on in 2004.
In another few weeks it will be clear for them.
I don't think this was predictable. You really have to be on the ground to see what the conditions are to make a call on whether it is safe or not. Two months ago on the 6 October I blogged about the sea ice and the potential of this happening, and said:
There are a lot of Antarctic research stations on the west of the Antarctic Peninsula, including Rothera, the largest British Base. If the winds maintain the westerly direction then I can imagine it could be slow to resupply the base this season. There is time for it to change. According to the published schedule the ship is not due to arrive until 27 November 2016.
A slow resupply is not uncommon and I have been on at least one unsuccessful resupply voyage in my career. I took the picture below on 11 December 2004 under similar conditions.
Although it is not predictable, the fantastic British Antarctic Survey Operations will have planned for the consequences.
For a last point on the left of the navigational chart is one of my favourite place names:
As it says on the UK Antarctic Place Names website:
Fullastern Rock (67° 36′ 58″ S, 69° 25′ 59″ W) is a submerged rock on the west side of Johnston Passage, to the west of Adelaide Island. It was first charted by a Royal Navy Hydrographic Survey Unit from RRS John Biscoe in 1963. The ship was compelled to go full astern to avoid this hazard – a story succinctly captured by this evocative name!