From the bridge of the Akademik Shokalskiy, it was hard to notice the weather change at first.
The sharp line of the horizon was just starting to blur – a telltale sign that wind high on the Antarctic plateau was whipping up snow and heading for the coast where the Russian-flagged ship was parked against the frozen edge of the continent. A forecast from meteorologists at one of Australia's Antarctic research bases, Casey station, had predicted southeasterly winds would strengthen late in the day, the 23rd of December.
For Greg Mortimer, an experienced Antarctic guide and the voyage leader onboard the Shokalskiy, the poor visibility meant one thing: the weather was closing down early. It was about 2.30pm. The ship's captain, Igor Kiselev, was also visibly worried, according to passengers on the bridge. It was time for the ship to leave. But some of the Shokalskiy's passengers were still out on the ice.
''The group had no indication of a threatening body of ice in the vicinity.''
In a report submitted to the International Association of Antarctic Tour Operators, and seen by the Fairfax, Mortimer wrote that Kiselev advised him that slabs of free floating sea ice were closing in around the ship, blocking her escape route.
Mortimer, who was in charge of the logistical operations of the voyage, made the decision to get everyone off the ice. "At this stage we were more concerned with the potential white-out onshore than potential for getting caught in the ice," he wrote.
At that moment, 22 people were on the ice, including the leaders of the expeditions, Illawarra-based Professor Chris Turney and Dr Chris Fogwill, both scientists from the University of NSW. Of those 22 people, 15 were about five nautical miles from the ship at a place called the Hodgeman Islands - about a 25 minute ride in a snow vehicle. More than four hours would pass from the time Mortimer sounded the alarm and when the Shokalskiy would back out of the fast ice and make a dash for open water at 6.15pm.
It was the start of a chain of events that would leave the ship trapped in the ice for more than two weeks, triggering an international rescue effort that diverted four ships, and delayed the international Antarctic programs of four nations. The event will likely result in multimillion-dollar insurance claims.
Four days earlier, however, as the Shokalskiy sailed into Commonwealth Bay, the team was more than halfway through their journey following the path Sir Douglas Mawson's Australasian Antarctic Expedition (AAE) travelled 100 years earlier.
To retrace Mawson's voyage the AAE used the New Zealand tourism company Heritage Expeditions to sub-charter the Shokalskiy, an ice strengthened ship owned by the Russia government. Turney and Fogwill’s employer, UNSW, signed the sub-charter contract. The ship departed Bluff, New Zealand on December 8 bound for East Antarctica. It was due to return January 4. On board were 22 crew and 52 passengers, all members of the AAE 2013/14. Of the group, 19 were scientists or students and 24 paying passengers, often called science volunteers. Also on board were three Commonwealth-funded members of the Mawson's Hut Foundation, six expedition staff including a medical doctor, three Heritage Expedition staff and three members of Chris Turney's family.
On December 19, after 11 days at sea, the Shokalskiy sailed into Commonwealth Bay, to an area known as the Mertz polynya, where thousands of tonnes of sea ice are produced each year. It was also one of the easiest points to access Mawson's Hut. The expedition had planned to visit the famous huts, located at Cape Denison, but the leaders knew it would be difficult to get close to the coast. In 2010 an enormous iceberg, called B09B, became grounded on the seafloor to the bay's north. Since then a large expanse of sea ice has became trapped between the iceberg and the coastline. Turney and Fogwill said they studied the regular satellite images of the sea ice, which is called fast ice because it is fastened to the continent, in Commonwealth Bay for two to three years before the AAE voyage departed.
"That allowed us to know the fast ice edge was stable and the Mertz polynya was open," said Fogwill.
The leaders, including Mortimer, believed they could get to the huts safely by traversing the fast ice. On the 20th and 21st two small groups traversed 65 kilometres in snow vehicles, called Argos, to Mawson's Hut.
While the expedition leaders had hoped to get as many passengers to the hut as possible, Mortimer decided the five-hour journey was too far and dangerous to send more passengers. On December 22, with some time to spare, the Shokalskiy sailed east for about 30 hours, towards the Mertz glacier, to the Hodgeman Islands.
Both Turney and Fogwill were keen to visit the site, which was enclosed in fast ice but only five nautical miles from open water, to compare their scientific findings from Cape Denison, where they had found the terrestrial and marine wildlife adversely affected by the trapped sea ice. The area also provided a good location for the paying passengers to walk upon the Antarctic continent.
"There was an interesting opportunity to do some good science [and] to get the paying passengers underneath the icecap," Mortimer said.
After more than two weeks at sea, people were keen to feel Antarctica beneath their feet. "Everyone onboard was keen to make the journey across the fast ice to the islands," said one passenger.
After several hours negotiating pack ice, the Shokalskiy found a gap about 1.5 nautical miles wide and three nautical miles long which opened to the fast ice edge near the Hodgeman Islands.
The group leaders were, in part, guided to the fast ice edge by radar images provided by the University of Bremen, Germany and NASA satellite images of ice that were interpreted by sea ice experts at the University of Tasmania and the Antarctic Climate and Ecosystems Cooperative Research Centre in Hobart.
While radar and satellite images taken on December 20 and 21 revealed a clear fast ice edge near the Hodgeman Islands, images for the following two days were obscured by cloud which, according to Mortimer's report, meant they were "of no use to us".
In the days after the ship was beset Mortimer suggested it was possible that there had been a build up of heavy ice to the ship's south-east on December 22 and 23 that had been obscured by cloud in the image. But at the time, the group had no indication of a "threatening body of ice in the vicinity when we arrived in the area on the morning of 23 Dec", the report said. "Nor did the ice chart information suggest that," he wrote.
The director of the ACE CRC, Tony Press, said the satellite images were "as good a description as you can have of the situation".
"The satellite images showed where the sea ice was located and the weather forecast predicted increasing winds which would tell you that the sea ice could move."
The day the Shokalskiy passengers were evacuated onto his ship, the captain of the Aurora Australis, Murray Doyle, said the sea ice conditions around the Mertz glacier had changed significantly since 2010.
"Since the Mertz glacier was punched out by B09B [iceberg] some years ago it has changed the whole dynamics of the area," he said.
Significant sized sea ice floes were now building up year after year, he said.
The leaders were also receiving daily weather forecasts from three sources, the Bureau of Meteorology's forecasters at Casey station, a private forecasting company in Europe and the ship's onboard weather station. From this information Mortimer estimated the team had 15 to 18 hours before the weather deteriorated, and 24 hours before a more serious change was expected.
But the Bureau of Meteorology weather forecast issued the day before predicted high winds late on the 23rd.
Early that morning Mortimer recorded a southerly blowing at 10 to 15 knots.
"It was a beautiful day… a bit of wind but nothing out of the ordinary of what we'd seen on the previous [days and] on the rest of the journey," Turney said.
At about 10am, after the Captain had struggled to park the ship in the fast ice, three Argos were loaded into the water and towed to the ice edge with an inflatable boat, a Zodiac. But one Argo, with caterpillar tracks instead of wheels, was flooded during the tow. The group lost an hour and a half as staff retrieved the drowned vehicle, which was now useless. They were left with two quad bikes, which could ferry one driver and one passenger, and two Argos, which could carry five or six people.
Mortimer's report said: "We discussed the impact of losing 1.5hrs in dealing with the 3 Argo and felt that we had a sufficient time window to complete the operation.
"Decision taken that pax [passengers] would move quickly to Hodgeman Islands and either return immediately or return on next rotation of transport ie approximately 45 minutes later." he wrote.
One passenger said while the time wasted over the drowned Argo delayed the field trip by several hours the staff had gone to a lot of trouble to get passengers near the icecap.
"They probably didn't want to disappoint us. We were all rugged up and ready to go," they said.
"When you pay for an expedition to a place like Antarctica you trust that the leaders know what they’re doing.
At 12.30pm the first rotation of passengers set off for the Hodgeman Islands. They reported a smooth journey and some passengers set off to explore the nearby Adelie penguin rookery.
"Despite the wind and the extreme cold, the scenery on the journey was spectacular - it seemed unreal, as though we were on a movie set," said a passenger.
Each driver and staff member had a VHF radio. Both Turney and Fogwill carried satellite phones.
At 2.30pm when Mortimer saw the fuzz on the horizon and the captain warned of sea ice moving in behind the ship, the voyage leader used the ship's VHF radio to tell those with handheld VHF radios to move people back to the ship.
People at the Islands would later report they did not hear the message on their handhelds, which have a range of about five nautical miles.
Calls to both the satellite phones, which have a global range, went unanswered. There were 15 people at the islands including six staff, either drivers or field leaders.
At 3pm an Argo carrying four people returned to the ice edge.
A passenger, who was standing near Turney when Mortimer called the leader from the ship's VHF radio, recalled their conversation: "Chris, [captain] Igor has just said we need to expedite people back from the islands so we can get out of here," said Mortimer.
Turney, standing on the ice edge, repeated the message to confirm he had heard right. "Affirmative," said Mortimer. "If I take this lot out, how long can we stay?" Turney said. Mortimer repeated that everybody needed to get back to the ship.
The passenger was stunned by the conversation, even more so when, a few minutes later, Turney loaded an Argo with six passengers and drove off towards the Islands.
At 3.30pm the second Argo, this time with only a driver, was sent to evacuate the remaining passengers.
While Mortimer's report said the plan was for passengers to remain nearby the Islands and be closely supervised, several passengers said they were not aware of this request.
One passenger's written account of the day said: "Unknown to the passengers, the captain sent out a message that he was concerned and wanted everyone back on the ship as the weather was turning and he was worried about the ice coming in.
"Was it a communication problem or the optimism of those in charge?" Whatever the justification, one more load of passengers was taken out to the rookery, they said.
Greens senator-elect Janet Rice, who went out on the second trip to the Hodgeman's just after 12.30pm, said she was aware of a "weather window" but did not know there was a set time allowed in the field.
At 3.43pm a passenger onboard the Shokalskiy overheard Mortimer again speaking with someone on the VHF: "Everybody get into a small area and wait until they get a ride back. They [are] not to walk anywhere [and] are to [stay] together," the passenger wrote in their diary at the time. Fifteen minutes later a quad bike and an Argo arrived with another load of people, who were transferred to the ship via Zodiac.
"The anger on Greg's face when we arrived back was noticeable," said one passenger.
An hour and a half later and the final four on the ice, which included Turney, pulled up in the second Argo. Footage on a passenger’s Go Pro digital camera read 5.35pm.
It was 6.15pm before the Shokalskiy finally departed the fast ice.
Several passengers took video footage of the view from their porthole as the ship departed in open water. By 7pm ice topped with about a metre of snow surrounded the ship. It crawled through dense pack ice most of the night.
"The captain and his staff on the bridge did not look happy," a passenger said.
By 3am the next morning, Christmas Eve, the Shokalskiy was stuck. It also had a hole pierced through its portside bow, about three metres above the water - likely from its overnight ice ramming.
Passengers were told the damage would not compromise the structural integrity of the ship, but the hole worried some. It took the crew two days to repair.
At some point on Christmas Eve the captain became concerned about two icebergs floating near the ship. While sea or pack ice travels with the wind, icebergs, which hold 90 per cent of their mass below the surface, move with the current.
At 8.30am on Christmas morning the captain sent a distress message.
When Kielev spoke to the agency that manages search and rescues in Australian territorial waters, the Rescue Co-ordination Centre, a short time later he explained the Shokalskiy required an icebreaker to set her free. At the time, the ship was between two and four nautical miles from open water.
By 11.30am the RCC had sent three ships, the French L’Astrolabe, the Chinese Xue Long and the Australian Aurora Australis to assist.
On Christmas Day and Boxing Day, 50 knot winds, gusting up to 70 knots, from the south-east battered the ship and likely pushed a large breakout of sea ice around the vessel. Satellite images showed it was now 20 nautical miles from open water.
After the vessel had been beset for 10 days, on January 2, a co-ordinated rescue by the Chinese and Australian icebreakers evacuated the 52 passengers from the Shokalskiy to the Aurora Australis. "They're pretty lucky. It's very rare to have three ships in this part of Antarctica to help," Captain Doyle said.
When Mortimer looked out the window as he flew in the Xue Long's helicopter he was shocked by the massive expanse of ice that surrounded the Shokalskiy. "All that ice has blown in, in the past week. And its big, multi-year ice under enormous pressure," he said on the evening of the rescue.
"A catastrophic event has taken place in the last week, and we were party to that," he said.
One passenger remarked that the afternoon spent at the Hodgeman's had been one of the "greatest days of my life".
"To see the ice cap was amazing and terrifying at the same time."
Another passenger commented: "I had a great time on the day but I'm not sure it was worth three weeks of my life [stuck on the Shokalskiy and later onboard the rescue ship]."
While Antarctica's weather is unforgiving and its sea ice unpredictable, Mortimer's report also suggested human failures were to blame for the expedition’s dramatic end.
In his concluding remarks the Antarctic veteran referred to a "breakdown in our plans" to move people in and out of the Hodgeman Islands, which caused a two-hour delay, as one of the contributing factors.
While the group experienced problems with their VHF radios at the islands, the two satellite phones had gone unanswered.
And the plan to transfer passengers for a short 10 to 15 minute stay at the Hodgeman’s was not adhered too.
"In my view, it is the breakdown in this that may have been a contributing factor leading to the vessel becoming stuck in the ice," wrote Mortimer.
His finals remark credits the captain, who acted impeccably throughout the ordeal.
Mortimer, Turney, Fogwill and the 49 other Shokalskiy passengers arrived in Hobart on January 22, greeted by the world's media. With the passage of time, some passengers will likely remember the past month as a grand Antarctic adventure, but the repercussions of the ill-fated expedition may be significant for the leaders.
In the days following their rescue, Turney said the insurance claims were "yet to be discussed".
"Who is paying? At the moment, we're not sure," he said.
This account has been reconstructed from interviews with members of the Australasian Antarctic Expedition 2013/14, most of whom wished to remain anonymous, who witnessed events or overheard conversations, and the report the voyage leader, Greg Mortimer, submitted to IAATO.
Mortimer declined to comment on his report.
The Shokalskiy's captain, Igor Kielev, did not respond to Fairfax Media's emails.
Chris Turney and Chris Fogwill, the expedition leaders, also declined to comment on specific questions regarding events on December 23.
Nicky Phillips and Colin Cosier travelled on board the Aurora Australis as part of the Australian Antarctic Division's media fellowship program.