Monday, 21 November 2016

On to the Strait of Magellan

Events of Sunday, 20th November (Afternoon)

After lunch, I worked on the computer for a while before going to the Panorama Lounge for afternoon tea. Another Trivia Quiz was in progress but since the subjects were ‘Prehistoric Animals’ and ‘Food around the World’, I didn’t feel that I could contribute anything. However, the quiz rather ended in disarray following an announcement over the Public Address that Orca whales had been spotted to starboard and encouraging all passengers to come out on deck. There was a mass exodus towards the observation decks, fore and aft. Many of the passengers, including me, were only in indoor clothes but it was a warm afternoon with no wind in the sheltered waters so it was very enjoyable.

On an expedition ship like ‘Silver Explorer’, it’s not unusual for plans to change at short notice so I was not surprised when the ship abandoned its original course and turned to place us nearer the location of the sighting. An extraordinary period of half an hour or so followed as the guests gasped in amazement each time the massive creatures appeared at the surface.

There was a pod of at least four whales, identified by the Expedition Team as South Atlantic Orcas, probably sub-type A. We were told that it’s unusual to find them this far north. To avoid disturbing the whales, the ship did not attempt too close an approach but our sighting as rated as ‘very good’ by our field experts. Certainly the whales made no attempt to move away, although they would certainly have been aware of the ship. Eventually, the whales were seen to be slowly moving northwards so the sighting was terminated and the ship resumed its southern route. I'm afraid I didn't have my camera with me to record the scene but, in any case, neither my camera nor its owner are very well suited for nature photography.

The Orca sighting had overlapped the planned start of the five o’clock lecture, which was duly deferred to 5.15 p.m., when we were entertained by an informative and amusing lecture by Peter Damisch, the historian on the expedition team, entitled ‘Search for the Unknown Antarctic Continent’. A little later, the usual ‘Recap and Briefing’ took place in the theatre, where the programme for the next day was laid out (we were to have another ‘day at sea’ as we continued to Punta Arenas). There was then discussion and questions regarding the whale sighting and the birds observed to which a number of members of the Expedition Team contributed.

Another splendid evening meal followed which I enjoyed with a couple originally from England but now retired to Australia. During the meal, we passed a small cargo ship with three self-unloading cranes going north but I failed to identify it. This was the first ship I’d noticed since we came through English Narrows.

Aboard 'Silver Explorer': View from the restaurant as we pass a northbound cargo ship.

This was not quite the end of the evening. The friendly and attentive restaurant staff urged my companions and I to go the Panorama Lounge at ten o’clock where three members of the restaurant staff forming ‘The Crew Band’ were to sing for the guests to the music of the resident pianist. It was a jolly end to the evening before retiring to bed.

Aboard 'Silver Explorer': Vocals by members of the waiting staff in the Panorama Lounge.

Related Posts

Next post describing this trip: Cruising to Punta Arenas.
All posts describing this trip: Chilean Fjords.

My pictures

Where necessary, clicking on an image above will display an 'uncropped' view or, alternately, my pictures from this (and earlier) trips may be selected, viewed or downloaded, in various sizes, from the albums listed:-

Pictures aboard 'Silver Explorer' are here.
All my pictures of Chile can be found in the collection Chile.

[Events date and Orca type corrected: 24-Nov-2016. Link to pictures added, picturers added: 25-Jan-2017]

Pio XI Glacier

Events of Sunday, 20th November (Morning)

I awoke to a glorious sunny morning at our anchorage a mile or so short of the glacier face of the Pio XI glacier, originally called the Bruggen Glacier. This glacier is the largest outflow to the west from the Southern Patagonian Ice Field.

Glacier theory

Glaciers are produced in land areas where annual snowfall exceeds the rate of annual melting. Over a long period, as the thickness of snow increases, gravity crushes the lower layers of snow, expelling entrained air bubbles and creating dense, clear ice under pressure. Gravity also causes the dense ice mass to slowly slide towards lower ground at a speed determined by the topography and the frictional resistance to the ice movement presented by the underlying rock. This rock becomes fractured and ground by the ice and carried along with the glacial movement, often as a dark-coloured ‘moraine’. Where a glacier meets a fjord, pressure from the glacier further ‘upstream’ on the unsupported ice causes fracturing and the creation of an exposed glacier front. As pressure is relieved within the ice, the glacier face continues to fracture and ice breaks away in a process called ‘calving’.

The location

Pio XI is the longest glacier in the southern hemisphere outside Antarctica at about 64 km long. Whilst most glaciers are currently ‘in retreat’, between 1945 and 1976, this glacier advanced by around 5 km. The glacier face is 4.5 km wide but gives the impression of being smaller because, viewed from the fjord, there is little to give a sense of scale. In the case of Pio XI, the glacier is set between green, wooded hills and the proximity of mature trees offers some hint as to the true size of the glacier but it is difficult to avoid underestimating the scale of such an unfamiliar object.

Pio XI Glacier.

The Zodiac Cruise

Conditions were ideal for a Zodiac Cruise. Since it was planned that we would be on the water for 1.5 hours, we were warned to wear sufficient clothing to remain warm whilst sedentary. I made sure that I had a substantial breakfast and was ready in good time for when my group was called by public address to deck 3 for boarding the Zodiacs.

The first Zodiac away from the ship was driven by botanist Hans Peter in one of the larger Zodiacs. I was in the second Zodiac, driven by Luke and, with just 8 passengers, we had plenty of room. We sailed towards the glacier face which rose like a cliff from a ‘beach’ of ground-up rock of moraine materials.The glacier face was heavily fissured as pressures within the glacier had been relieved by cracking. Quite frequently, a loud rumbling like thunder could be heard as the glacial ice ‘re-arranged’ itself and, on a few occasions during our Zodiac cruise, this was accompanied by a visible fall of ice producing a white spray as the internal pressure produced an explosive release of material. The internal pressure had also resulted in crevasses in the top surface of the glacier leaving a very uneven appearance.

Pio XI Glacier Zodiac Cruise: Cliff-like glacier face and heavily-crevassed top surface.

As we came a little closer, the sea was littered with ice ranging from a few inches to a few feet across which had fallen from the glacier front. Sometimes the shape of the ice suggested a shard which had broken away from the glacier face, but often partial thawing and re-freezing had produced a strangely-shaped object, like some example of modern art. Only around 10% of each lump of ice is visible above the surface so care is needed when passing through ice debris called ‘brash ice’ and ‘bergy bits’.

Luke identified two types of ice. The first type has a white appearance, like frozen snow. The colour is produced by small air bubbles trapped in the ice. The second type is translucent without bubbles where pressures within the glacier have expelled the trapped air, leaving frozen water. This type of ice, in a large piece, takes on a bluish tinge because of the differential light absorption of water and water/air.

Luke also demonstrated the effect of holding a small, flat piece of ice containing air bubbles between both palms. As the body heat warms the ice, release of trapped air produces a series of audible ‘pops’, each accompanied by a slight vibration which can be felt. The air may have been imprisoned for thousands of years and laboratory tests now exist for releasing the air from samples of ice and analysing it to determine changes in the earth’s atmosphere.

Hans Peter, the botanist, presented our Zodiac with a piece of Kelp he’d found floating. Kelp grows rapidly as a series of broad leaves a couple of metres long, interconnected by flexible stems with air bladders. Each leaf is green, slightly corrugated and covered with a thin layer of mucous material. Normally, one end of the plant would be anchored to rock but wind and tide can break the stem, as had happened to the sample we examined.

Pio XI Glacier Zodiac Cruise: Luke displays the kelp presented by Hans Peter.

We spent some time cruising across the face of the glacier but keeping a respectful distance and examining the floating ice. At one location, the ice contained moraine material and was dark coloured. As the sun melted the ice, the crushed rock was released as sediment.

Crew Safety Drill

We had been advised that the ship’s crew were carrying out a safety drill whilst we were on the Zodiac Cruise but we didn’t know the details so, looking back at the ship, it was a surprise to see that one of the lifeboats had been launched. At the same time, a strange noise alerted us to the fact that we were being filmed by Ray from his drone hovering above us! I was delighted when we headed towards the lifeboat as I had not seen one in the water, only stowed on the davits.

Pio XI Glacier Zodiac Cruise: One lifeboat had been launched in a Crew Safety Drill.

Silver Explorer has two motorised lifeboats, each capable of holding 150 people. We drew alongside the lifeboat and I was amazed to see various members of the restaurant staff on board who presented us with a glass of champagne, cake and a variety of sweetmeats. The captain had agreed to let an essential training exercise serve a second, delightful purpose.

Our Zodiac then returned us to the ship after a wonderful cruise. Noticing that the lifeboat was about to be recovered, I hurried to the observation deck in time to see the electric winch lift the lifeboat out of the water and swing the davit arms and lifeboat into the ‘stowed’ position.

Aboard 'Silver Explorer': Following the Crew Safety Drill, the lifeboat is returned to the davits.

Once all the passengers were back on board and the Zodiacs recovered, we set off south again, this time on a ‘leg’ of 447 miles to Punta Arenas which would take more than one day. Meanwhile, I had a little time to work on the computer before lunch and a programme of lectures was offered during the afternoon.

Related Posts

Next post describing this trip: On to the Strait of Magellan.
All posts describing this trip: Chilean Fjords.

My pictures

Where necessary, clicking on an image above will display an 'uncropped' view or, alternately, my pictures from this (and earlier) trips may be selected, viewed or downloaded, in various sizes, from the albums listed:-

Pictures on the Pio XI Zodiac Cruise are here.
Pictures aboard 'Silver Explorer' are here.
All my pictures of Chile can be found in the collection Chile.

[Pictures added 13-Jan-2017]