Comparing sea ice today to Shackleton’s Ill Fated Voyage – 100 years ago this month

By Paul Homewood

100 years ago last week, Ernest Shackleton was preparing to depart from South Georgia with the Endurance on the Trans-Antarctic Expedition.

As is well known, he ended up trapped in pack ice the following January in the Weddell Sea, only a few miles from the coast. What followed was one of the most inspiring stories of bravery, heroism and suffering that could be imagined.

What is less well known, however, is that for over a month or more, the Endurance had battled for hundreds of miles through pack ice, to get to its point of no return.

Shackleton’s own book “South – the story of Shackleton’s last expedition, 1914-1917” contains much detail and insight into this early part of the expedition. Below is a lengthy extract from Chapter 1. You can skim over if you want, but it is worth the read.

I had decided to leave South Georgia about December 5, and in the intervals of final preparation scanned again the plans for the voyage to winter quarters. What welcome was the Weddell Sea preparing for us? The whaling captains at South Georgia were generously ready to share with me their knowledge of the waters in which they pursued their trade, and, while confirming earlier information as to the extreme severity of the ice conditions in this sector of the Antarctic, they were able to give advice that was worth attention.

It will be convenient to state here briefly some of the considerations that weighed with me at that time and in the weeks that followed. I knew that the ice had come far north that season and, after listening to the suggestions of the whaling captains, had decided to steer to the South Sandwich Group, round Ultima Thule, and work as far to the eastward as the fifteenth meridian west longitude before pushing south. The whalers emphasized the difficulty of getting through the ice in the neighbourhood of the South Sandwich Group. They told me they had often seen the floes come right up to the group in the summer-time, and they thought the Expedition would have to push through heavy pack in order to reach the Weddell Sea.

During December 6 the ‘Endurance’ made good progress on a southeasterly course. The northerly breeze had freshened during the night and had brought up a high following sea. The weather was hazy, and we passed two bergs, several growlers, and numerous lumps of ice. Staff and crew were settling down to the routine. Bird life was plentiful, and we noticed Cape pigeons, whale-birds, terns, mollymauks, nellies, sooty, and wandering albatrosses in the neighbourhood of the ship. The course was laid for the passage between Sanders Island and Candlemas Volcano. December 7 brought the first check. At six o’clock that morning the sea, which had been green in colour all the previous day, changed suddenly to a deep indigo. The ship was behaving well in a rough sea, and some members of the scientific staff were transferring to the bunkers the coal we had stowed on deck. Sanders Island and Candlemas were sighted early in the afternoon, and the ‘Endurance’ passed between them at 6 p.m. Worsley’s observations indicated that Sanders Island was, roughly, three miles east and five miles north of the charted position. Large numbers of bergs, mostly tabular in form, lay to the west of the islands, and we noticed that many of them were yellow with diatoms. One berg had large patches of red-brown soil down its sides. The presence of so many bergs was ominous, and immediately after passing between the islands we encountered stream-ice. All sail was taken in and we proceeded slowly under steam. Two hours later, fifteen miles north-east of Sanders Island, the ‘Endurance’ was confronted by a belt of heavy pack-ice, half a mile broad and extending north and south. There was clear water beyond, but the heavy southwesterly swell made the pack impenetrable in our neighbourhood. This was disconcerting. The noon latitude had been 57° 26´ S., and I had not expected to find pack-ice nearly so far north, though the whalers had reported pack-ice right up to South Thule.

The situation became dangerous that night. We pushed into the pack in the hope of reaching open water beyond, and found ourselves after dark in a pool which was growing smaller and smaller. The ice was grinding around the ship in the heavy swell, and I watched with some anxiety for any indication of a change of wind to the east, since a breeze from that quarter would have driven us towards the land. Worsley and I were on deck all night, dodging the pack. At 3 a.m. we ran south, taking advantage of some openings that had appeared, but met heavy rafted packice, evidently old; some of it had been subjected to severe pressure. Then we steamed north-west and saw open water to the north-east. I put the ‘Endurance’s’ head for the opening, and, steaming at full speed, we got clear. Then we went east in the hope of getting better ice, and five hours later, after some dodging, we rounded the pack and were able to set sail once more. This initial tussle with the pack had been exciting at times. Pieces of ice and bergs of all sizes were heaving and jostling against each other in the heavy south-westerly swell. In spite of all our care the ‘Endurance’ struck large lumps stem on, but the engines were stopped in time and no harm was done. The scene and sounds throughout the day were very fine. The swell was dashing against the sides of huge bergs and leaping right to the top of their icy cliffs. Sanders Island lay to the south, with a few rocky faces peering through the misty, swirling clouds that swathed it most of the time, the booming of the sea running into ice-caverns, the swishing break of the swell on the loose pack, and the graceful bowing and undulating of the inner pack to the steeply rolling swell, which here was robbed of its break by the masses of ice to windward.

We skirted the northern edge of the pack in clear weather with a light south-westerly breeze and an overcast sky. The bergs were numerous. During the morning of December 9 an easterly breeze brought hazy weather with snow, and at 4.30 p.m. we encountered the edge of pack-ice in lat. 58° 27´ S., long. 22° 08´ W. It was one-year-old ice interspersed with older pack, all heavily snow-covered and lying westsouth-west to east-north-east. We entered the pack at 5 p.m., but could not make progress, and cleared it again at 7.40 p.m. Then we steered east-north-east and spent the rest of the night rounding the pack. During the day we had seen adelie and ringed penguins, also several humpback and finner whales. An ice-blink to the westward indicated the presence of pack in that direction. After rounding the pack we steered S. 40° E., and at noon on the 10th had reached lat. 58° 28´ S., long. 20° 28´ W. Observations showed the compass variation to be 1½° less than the chart recorded. I kept the ‘Endurance’ on the course till midnight, when we entered loose open ice about ninety miles south-east of our noon position. This ice proved to fringe the pack, and progress became slow. There was a long easterly swell with a light northerly breeze, and the weather was clear and fine. Numerous bergs lay outside the pack.

The ‘Endurance’ steamed through loose open ice till 8 a.m. on the 11th, when we entered the pack in lat. 59° 46´ S., long. 18° 22´ W. We could have gone farther east, but the pack extended far in that direction, and an effort to circle it might have involved a lot of northing. I did not wish to lose the benefit of the original southing.

On the morning of December 12 we were working through loose pack which later became thick in places. The sky was overcast and light snow was falling. I had all square sail set at 7 a.m. in order to take advantage of the northerly breeze, but it had to come in again five hours later when the wind hauled round to the west. The noon position was lat. 60° 26´ S., long. 17° 58´ W., and the run for the twenty-four hours had been only 33 miles. The ice was still badly congested, and we were pushing through narrow leads and occasional openings with the floes often close abeam on either side.

We found several good leads to the south in the evening, and continued to work southward throughout the night and the following day. The pack extended in all directions as far as the eye could reach. The noon observation showed the run for the twenty-four hours to be 54 miles, a satisfactory result under the conditions.

The conditions became harder on December 14. There was a misty haze, and occasional falls of snow. A few bergs were in sight. The pack was denser than it had been on the previous days. Older ice was intermingled with the young ice, and our progress became slower. The propeller received several blows in the early morning, but no damage was done. A platform was rigged under the jib-boom in order that Hurley might secure some kinematograph pictures of the ship breaking through the ice. The young ice did not present difficulties to the ‘Endurance’, which was able to smash a way through, but the lumps of older ice were more formidable obstacles, and conning the ship was a task requiring close attention. The most careful navigation could not prevent an occasional bump against ice too thick to be broken or pushed aside. The southerly breeze strengthened to a moderate south-westerly gale during the afternoon, and at 8 p.m. we hove to, stem against a floe, it being impossible to proceed without serious risk of damage to rudder or propeller. I was interested to notice that, although we had been steaming through the pack for three days, the north-westerly swell still held with us. It added to the difficulties of navigation in the lanes, since the ice was constantly in movement.

The ‘Endurance’ remained against the floe for the next twenty-four hours, when the gale moderated. The pack extended to the horizon in all directions and was broken by innumerable narrow lanes. Many bergs were in sight, and they appeared to be travelling through the pack in a south-westerly direction under the current influence. Probably the pack itself was moving north-east with the gale. Clark put down a net in search of specimens, and at two fathoms it was carried south-west by the current and fouled the propeller. He lost the net, two leads, and a line. Ten bergs drove to the south through the pack during the twenty- four hours. The noon position was 61° 31´ S., long. 18° 12´ W. The gale had moderated at 8 p.m., and we made five miles to the south before midnight and then we stopped at the end of a long lead, waiting till the weather cleared. It was during this short run that the captain, with semaphore hard-a-port, shouted to the scientist at the wheel: “Why in Paradise don’t you port!” The answer came in indignant tones: “I am blowing my nose.”

The ‘Endurance’ made some progress on the following day. Long leads of open water ran towards the south-west, and the ship smashed at full speed through occasional areas of young ice till brought up with a heavy thud against a section of older floe. Worsley was out on the jibboom end for a few minutes while Wild was conning the ship, and he came back with a glowing account of a novel sensation. The boom was swinging high and low and from side to side, while the massive bows of the ship smashed through the ice, splitting it across, piling it mass on mass and then shouldering it aside. The air temperature was 37° Fahr., pleasantly warm, and the water temperature 29° Fahr. We continued to advance through fine long leads till 4 a.m. on December 17, when the ice became difficult again. Very large floes of sixmonths-old ice lay close together. Some of these floes presented a square mile of unbroken surface, and among them were patches of thin ice and several floes of heavy old ice. Many bergs were in sight, and the course became devious. The ship was blocked at one point by a wedge-shaped piece of floe, but we put the ice-anchor through it, towed it astern, and proceeded through the gap. Steering under these conditions required muscle as well as nerve. There was a clatter aft during the afternoon, and Hussey, who was at the wheel, explained that “The wheel spun round and threw me over the top of it!” The noon position was lat. 62° 13´ S., long. 18° 53´ W., and the run for the preceding twenty-four hours had been 32 miles in a south-westerly direction. We saw three blue whales during the day and one emperor penguin, a 58-lb. bird, which was added to the larder.

The morning of December 18 found the ‘Endurance’ proceeding amongst large floes with thin ice between them. The leads were few. There was a northerly breeze with occasional snow-flurries. We secured three crab-eater seals—two cows and a bull.  I had been prepared for evil conditions in the Weddell Sea, but had hoped that in December and January, at any rate, the pack would be loose, even if no open water was to be found. What we were actually encountering was fairly dense pack of a very obstinate character. Pack-ice might be described as a gigantic and interminable jigsaw-puzzle devised by nature. The parts of the puzzle in loose pack have floated slightly apart and become disarranged; at numerous places they have pressed together again; as the pack gets closer the congested areas grow larger and the parts are jammed harder till finally it becomes “close pack,” when the whole of the jigsaw-puzzle becomes jammed to such an extent that with care and labour it can be traversed in every direction on foot. Where the parts do not fit closely there is, of course, open water, which freezes over, in a few hours after giving off volumes of “frost-smoke.” In obedience to renewed pressure this young ice “rafts,” so forming double thicknesses of a toffee-like consistency. Again the opposing edges of heavy floes rear up in slow and almost silent conflict, till high “hedgerows” are formed round each part of the puzzle. At the junction of several floes chaotic areas of piled-up blocks and masses of ice are formed. Sometimes 5-ft. to 6-ft. piles of evenly shaped blocks of ice are seen so neatly laid that it seems impossible for them to be Nature’s work. Again, a winding canyon may be traversed between icy walls 6 ft. to 10 ft. high, or a dome may be formed that under renewed pressure bursts upward like a volcano. All the winter the drifting pack changes—grows by freezing, thickens by rafting, and corrugates by pressure. If, finally, in its drift it impinges on a coast, such as the western shore of the Weddell Sea, terrific pressure is set up and an inferno of ice-blocks, ridges, and hedgerows results, extending possibly for 150 or 200 miles off shore. Sections of pressure ice may drift away subsequently and become embedded in new ice.

I have given this brief explanation here in order that the reader may understand the nature of the ice through which we pushed our way for many hundreds of miles. [This is Shackleton’s comment by the way!]

Shackleton continues in the same vein until the ship becomes totally trapped on January 19th. His account is fascinating, giving a good description of life on board. The book appears to be fully available online here, and I would recommend reading it in more depth.

However, I thought it would be interesting to compare some of the locations where he reports pack ice with current conditions.

The first location he mentions is on Dec 9th.

During the morning of December 9 an easterly breeze brought hazy weather with snow, and at 4.30 p.m. we encountered the edge of pack-ice in lat. 58° 27´ S., long. 22° 08´ W.

As located on Google Earth:

The ring of islands to the west is the South Sandwich Islands, which include Sanders and Candlemas Islands, where Shackleton mentions the first contact with pack ice three days earlier.

We can plot the track over the next few days, till Dec 17th. Every day during that period, the Endurance appears to have been sailing through, or close to, pack ice.

We can compare these locations with the current extent of sea ice,provided by the University of Bremen using satellite data.

http://www.iup.uni-bremen.de:8084/amsr2/antarctic_AMSR2_visual.png

I have zoomed in on the area around the South Sandwich Islands. Inside my highly artistic(!) circle, can be seen the three most northerly of the eight main islands, and to the north west is the larger island of South Georgia.

This would put the current ice edge of the ice pretty much where Shackleton also found it in 1914. (The most southerly island visible on the map below is Candlemas, located at 57.05S/26.39W. Shackleton first met pack ice at 58.27S/22.08W).

Shackleton noted that the ice appeared to be further north that year, just as it is at the moment in that area, according to NSIDC.

http://nsidc.org/data/seaice_index/index.html#

Although we have been bombarded with theories of why Antarctic sea ice has been expanding, the most remarkable thing is just how little things have actually changed since the days of Shackleton.