CHAPTER III
LAND ICE
Under the conditions of low temperature which have been described, even if there is only a very slight snowfall in the heart of Antarctica, there must be a constant accumulation of snow upon the land. This snow by its own incumbent weight gets compressed into ice, which fills corries and glens, and covers any flat land there may be with a great depth of solid ice. But the accumulation cannot go on indefinitely, and the ice begins to flow, first down the steeper glens, then down even the least inclined stretches of the land, forced by the great mass of ice always accumulating from behind. It may even get pushed over flat if not actually rising ground, and eventually reaches the sea. If the sea be shallow it may push out a considerable distance from the land, ultimately floating free from the bottom. Fresh snow is all the while falling, and adding to the whole. Blizzards come and drive the powdery loose snow from one place to another, and the hard-driving wind binds the powder into solid ice. Imagine all this on an enormous scale! Not over an area of a dozen or a hundred, or even a thousand square miles, but over an area as large as Europe and Australia combined, then we have a picture of what is happening over the length and breadth of Antarctica! The ice thus accumulated from snowfall, thus consolidated from loose snow into solid ice by pressure, gets pushed ultimately into the sea. Let me indicate what happens by referring for a moment to a phenomenon with which all of us are familiar. A snowstorm whitens all the country round and every roof has a coating of snow some six inches thick. The snow gets bound together and remains a more or less solid covering on the roof, till one day it slips off from various causes in irregular pieces, all about six inches thick and perhaps several feet across, and crashes down on the roadway beneath. But if the eaves of the roof dipped into water at that level, then this great sheet of icy snow would, when slipping from the roof, float off on the surface of the water. The floating sheets of icy snow—"floating ice islands"—would be of various areas, but they would all be flat-topped, and of a uniform thickness of six inches, the sides would be more or less perpendicular, and the greater part of the thickness would be below the surface of the water, the amount depending on the solidity of each sheet of icy snow, but possibly one inch might be above water to five inches below. Magnify your roof, magnify your ice covering which has slipped off the roof and floated off into the water, magnify your snowfall of a single night into that of more than a thousand years, make every inch of thickness 100 feet, and you have models on a scale of 1 to 1,200 of Antarctic icebergs, at least as far as shape is concerned. The mode of formation also is somewhat similar to that of the Antarctic icebergs, although probably the great ice-fields that come flowing over extensive stretches of gently undulating or more or less flat land, and even what would be shallow sea were the ice not there, are fed not only by the intermittent falls of snow year after year and by the drift brought from the mountains and inland ice, but also by glaciers which act as feeders to these low-lying ice-fields, and which keep on pushing the whole mass seaward until great flat-topped pieces, exactly similar in shape to the flat-topped snow islands from the roof, float out to sea.
One of these great ice-fields lies to the south of New Zealand, terminating in an ice cliff in the Ross Sea, which is usually known as the Ross Barrier. This great barrier was discovered by Ross in 1840, and was visited by him during two successive seasons. It has been now visited by several expeditions during recent years, especially by those under the leadership of Scott and Shackleton. This ice cliff, varying in height from almost sea-level to about 100 feet above the sea, stretches in an east and west direction between Mounts Erebus and Terror and Edward Land for a distance of nearly 300 miles. It is quite easy to imagine that pieces many miles in length and breadth might break off and float out to sea, as well as almost innumerable smaller pieces from a mile or two in length and breadth to only a few feet. This is exactly what does happen, and it certainly must occur in other parts of the Antarctic Regions besides the Ross Sea. Those countless bergs seen by us on board the Balæna in 1892–93, and again those seen by all on board the Scotia during her two cruises in the Weddell Sea, as well as those that drifted past the South Orkneys for eight months during the winter of 1903, and those seen by Charcot between 70° W. and 124° W., certainly did not come from the Ross Barrier, but from similar barriers, perhaps even more extensive than the Ross Barrier. Other barriers must occur elsewhere in the Antarctic Regions to account for the host of table-topped bergs that are scattered all over the Great Southern Ocean, and indeed Nordenskjold has described one on the east coast of Graham Land. The greater size of the bergs on the Atlantic Ocean than on the Pacific side of Antarctica indicates the greater scale of the ice-sheet towards the Weddell Sea than towards the Ross Sea. Moreover, after the reports of the latest expeditions, it appears probable that the larger and more numerous bergs that occur to the south of the Atlantic and Indian Oceans are not wholly comparable in their formation and structure to those found in the Ross Sea, in the neighbourhood of the Ross Barrier.
The whole question of the Ross Barrier and a barrier described by Nordenskjold on the east coast of Graham Land, which he calls an "ice-terrace," is most interesting. Buchanan and Nordenskjold have pointed out that these barriers, or ice-terraces, are composed of névé, not glacier ice, and with the Graham Land Barrier this especially appears to be the case. Névé, however, precludes the idea of flow, and we have the definite record of Scott that Barne, on visiting a dépôt Scott had laid down, found that it had "moved on." "Thirteen and a half months," says Scott, "after the establishment of the dépôt, he measured its displacement, and found it to be 606 yards. And thus almost accidentally we obtained a very good indication of the movement of the Great Barrier ice-sheet." (The Voyage of the Discovery, Captain R. F. Scott, vol. ii, p. 300: London, 1905.)
Doubtless, the Ross Barrier is fed considerably from the southern glaciers that run into it. Speaking of the discharges of the glaciers from the névé of the inland ice plateau, Scott says, "From observations which I have mentioned one must gather that the movement of this most northerly of these discharges is very slow, but judging by the movement of the Barrier, the southern ones are more active."
Now the only good channels by which glaciers run into this Barrier, and that are of importance and that come down from the Inland Ice-sheet or Inland névé over which Scott, Shackleton, Armitage, and David have led expeditions, probably come into it at half-a-dozen so-called inlets, such as Skelton, Mulock, Barne, and Shackleton Inlets, and the largest and most definite feeder known is the great glacier that Shackleton discovered and travelled up from the Barrier to the Inland Ice, namely, the Beardmore Glacier.
But the ice that pours out of this evidently rapid-flowing and huge glacier is about 360 nautical miles from the face of the cliff of the Ross Barrier. Now, according to Scott's estimated rate of flow of the Barrier at 606 feet in thirteen and a half months, it would take nearly 1,200 years for that ice to reach the Barrier face. Meantime the whole glacier—or should it be called ice-field?—is accumulating ice by snowfall and by drift from the surrounding mountains and plateaux, and must therefore be chiefly and, indeed possibly, wholly composed of this in the form of névé, but with this marked character, that it is a moving, and not a stationary, névé. At some future time, with more space at my disposal, I propose to further discuss this point, because a general definition of a névé is ice that collects in a lofty plain, from which glaciers flow out but which does not actually flow itself. The structure of névé ice is also distinct from that of glacier ice, the grain of which, in each case, is the leading feature. The flow of the Ross Barrier is, I believe, different from that of an ordinary glacier which comes running and tumbling down a gully or a glen, like water in a river down a river course, for in this case it comes over a low stretch of flat or gently shelving land or shallow sea and is ultimately afloat. It is rather pushed from behind than moving forward by its own gravitation. The flow is probably different also in this respect, that, like a rapid river, there is a sort of rotatory movement of the ice of a glacier which is plastic by virtue of its disintegrated grains, each surrounded with a film of saline water, whereas very little of such movement would occur in the case of the barrier ice, and consequently the marks of stratification remain visible in the bergs which are calved from it. Except for a certain amount of glacier ice, which comes in from the feeders mentioned, the Ross Barrier is made up almost entirely of successive years' additions of snow and drift that fall upon it and accumulate in definite layers. The simile, therefore, that I have already given of the snow layer on a roof is all the more striking, only it is not the accumulation of snow of a single fall, not even of snow of a single year, but probably of snow that has fallen, say, during a thousand years.
It would not do to pass by Nordenskjold's important observations with regard to his "ice terrace" at Graham Land, and it is best to quote his own words (Antarctica, Dr. Otto Nordenskjold: London, 1905) as follows: "At our noonday rest I was nearly falling into a broad crevasse, but said nothing of the matter, in order not to make the others anxious. But all of a sudden the ice became more uneven, and at 5 p.m. our march came to a sudden and unexpected end in front of a canal-like crevasse, some 20 metres (65 feet) broad and almost as deep, which seemed to run in towards the land as far as the eye could reach. This crevasse was of great interest, as it gave us a very clear idea of the inner structure of the ice. The same splendid stratification could be seen here as that which often occurs in the large icebergs, thus proving that the ice had been formed of layers of snow deposited, during long periods, the one upon the other, and being, too, a new proof of the transition, found in these regions, from glacier to sea ice. I think, too, that the Antarctic icebergs need not necessarily have their origin on land, but that they can also be built up on a base of sea ice in shallow water near the land."
Nordenskjold's idea that Antarctic icebergs may be built up on a base of sea ice is not altogether new, for Captain Cook previously made that suggestion, though without the great scientific qualifications that Nordenskjold has for expressing such an opinion, and also without the knowledge of the existence of these barriers or ice-terraces that have been discovered in the Antarctic Regions by Ross and Nordenskjold since Cook's voyage. But from my experience in the Polar Regions during twenty years I cannot conceive of these Antarctic bergs being built up from a base of sea ice.
There appears to be little doubt, however, that the Ross Barrier is to a great extent afloat. But Sir George Darwin's "guess" "that the bay behind the barrier stretches past the South Pole and to the east of it as far as latitude 80°" is dangerous. All the evidence at our disposal from observations taken in the region of the Weddell Sea condemns the idea that there is "an arm of the sea through to Weddell's Sea." (Tidal Observations of the British Antarctic Expedition, 1907. Sir G. Darwin.)
The question is a most intricate and difficult one, and cannot be properly solved until one or more expeditions set themselves to work in definitely making examinations of the ice of the different layers of the barriers, of the different layers of the bergs that have been shed from them, and various detailed measurements, and, what is perhaps as important as anything, the demarcation of the exact extent of these barriers, and a detailed survey of their surface as regards level. From the information we have at hand, it is very difficult to assert with certainty that the altitude of the Ross Barrier, when it emerges into the Ross Sea, is exactly the same as it is in 84° S., in the vicinity of the Beardmore Glacier.
It can be imagined that bergs of almost any length might be broken off from such a barrier as the Ross Barrier, and, as a matter of fact, bergs of enormous size have been recorded by many voyagers to the South Seas. Even allowing for exaggeration due to difficulty in gauging their length, bergs of several miles in length, up to 20 or 30, certainly do occur. A single glance at the ice chart for the Antarctic Regions published by the Admiralty will confirm this statement. On board the Balæna and the Scotia we saw many bergs at least 4 miles long: on one occasion, on the Balæna, we measured a berg 12 miles long, and on another occasion the Balæna steamed at the rate of 5 knots for 6 hours along the face of a berg, which made the length of it fully 30 miles. Some bergs have been recorded of very much greater height than any I have seen, though the records are doubted by some Antarctic explorers of recent years, but in bad weather and in those tempestuous seas it is easy for such errors to occur, though it may be possible to have bergs considerably more than 150 feet high in the Antarctic if, by weathering, one of these flat-topped bergs should become tilted up on end. These gigantic bergs have at times been described as ice islands, and by the inexperienced mistaken for land.
There is another class of icebergs in the Antarctic Regions that are rather overlooked and lost sight of by being overshadowed with so large a number of these great flat-topped bergs: these are bergs that are similar in every respect to those of the Arctic Regions. They are formed by much smaller and irregular pieces of ice breaking away from the snouts of glaciers similar to those found in Spitsbergen and other Arctic lands. These are only formed in smaller masses of land like the South Orkneys or those parts of the continent where relatively small individual glaciers run directly from the mountains into the sea, as they do at the northern extremity of Graham Land, at the South Orkneys, and several other places.
The reader should now have a clear conception of what bergs are and how they are formed. He will see that they are a product of the land, and that they are composed entirely of fresh-water ice. They may be likened to great ships, dwarfing the greatest liners and battleships into beggarly insignificance; they sail forth to the open ocean drifted by deeper currents rather than the wind, moving to and fro with the tide; blizzards and stormy seas lashing them, they drive onward with the currents of the sea, checked only by a contrary tide and helped onward by a favourable one; onward they go head to wind and head to sea, it matters little to them! Should some smaller berg be driven against one of these leviathans, it is dashed to pieces against its icy cliffs, only with the sacrifice of a few chips falling off and around its victim; should a field of floe ice be driven by the wind against it, the floe is broken into fragments, whilst pack ice divides and passes by on either side. They drive onward and northward all-conquering and resistless, and then venture forth into warmer seas. These seas are the most tempestuous in the world, and the presence of so much ice in water of a higher temperature not only encourages fogs, as does also the variation of the temperature of the air and water, but is exceedingly dangerous to ships navigating there; especially as in these latitudes there are always dark nights of greater or less duration the whole year. But this is the beginning of the end: rotted by the warmer winds and seas, gutted out with caves up which great waves rush in wild confusion into the very bowels of these monsters, the bergs get undermined, turn turtle, and break up into many smaller bergs and thousands of smaller irregular pieces. These irregular chips get still more weathered, and assume most fantastic shapes, and are hard as flint. They are the "growlers" and the "bergy bits" that we have already spoken of.
Many an iron ship has had its side or bottom ripped out with growlers, and many a wooden ship has had its wooden walls "stove-in" with them, and nothing more has been heard of them or their living human freight. No chance for these poor wretches, even if a few managed to scramble wet, cold, and benumbed into a ship's boats. No hand to help, no one to hear their last cry of agony. If this is the power of a "growler," what chance has a helpless sailing-ship driving before a gale with a monster berg on its lee? Her end must be a battering to death against its solid ice cliffs.
Even with ships specially constructed for ice-navigation, the greatest care has to be exercised. I have seen a relatively small piece weighing hundreds of tons falling off one of these great bergs; a smaller more weather-beaten berg splitting in two; and, on another occasion, a berg turning turtle. In each case a great wave was generated, and had our ship been in too close proximity it would certainly have resulted in serious damage and probable loss of life, if not total destruction. Several Antarctic ships have had narrow escapes when navigating, under force of circumstances, during dark nights in the vicinity of these great bergs; the serious collision of Ross's ships among a chain of bergs during a hard gale on a dark night, was an instance as notable as their miraculous escape. On this terrible night the Erebus was trying to weather a berg when it was observed that the Terror was running down upon her. It was impossible for the Terror to clear both the Erebus and the berg; collision was inevitable. Ross graphically describes the incident, and says, "We instantly hove all aback to diminish the violence of the shock; but the concussion when she struck us, was such as to throw almost every one off his feet; our bowsprit, fore-topmast, and other smaller spars, were carried away; and the two ships hanging together, entangled by their rigging, and dashing against each other with fearful violence, were falling down upon the lofty berg under our lee, against which the waves were breaking and foaming to near the summit of its perpendicular cliffs. Sometimes she rose high above us, almost exposing her keel to view, and again descended as we in our turn rose to the top of the wave, threatening to bury her beneath us, whilst the crashing of the breaking upper works and boats increased the horror of the scene. Providentially they gradually forged past each other, and separated before we drifted down amongst the foaming breakers, and we had the gratification of seeing her clear the end of the berg, and of feeling that she was safe. But she left us completely disabled; the wreck of the spars so encumbered the lower yards, that we were unable to make sail, so as to get headway on the ship; nor had we room to wear round, being by this time so close to the berg that the waves, when they struck against it, threw back their sprays into the ship. The only way left to us to extricate ourselves from this awful and appalling situation was by resorting to the hazardous expedient of a stern-board, which nothing could justify during such a gale and with so high a sea running, but to avert the danger which every moment threatened us of being dashed to pieces. The heavy rolling of the vessel, and the probability of the masts giving way each time the lower yard-arms struck against the cliffs, which were towering high above our mast-heads, rendered it a service of extreme danger to loose the mainsail; but no sooner was the order given, than the daring spirit of the British seaman manifested itself—the men ran up the rigging with as much alacrity as on any ordinary occasion; and although more than once driven off the yard, they after a short time succeeded in loosing the sail. Amidst the roar of the wind and sea it was difficult both to hear and to execute the orders that were given, so that it was three-quarters of an hour before we could get the yards braced bye, and the maintack hauled on board sharp aback—an expedient that perhaps had never before been resorted to by seamen in such weather: but it had the desired effect; the ship gathered stern-way, plunging her stern into the sea, washing away the gig and quarter boats, and, with her lower yard-arms scraping the rugged face of the berg, we in a few minutes reached its western termination; the 'under tow,' as it is called, or the reaction of the water from its vertical cliffs, alone preventing us being driven to atoms against it. No sooner had we cleared it than another was seen directly astern of us, against which we were running; and the difficulty now was to get the ship's head turned round and pointed fairly through between the two bergs, the breadth of the intervening space not exceeding three times her own breadth; this, however, we happily accomplished; and in a few minutes, after getting the wind, she dashed through the narrow channel between two perpendicular walls of ice, and the foaming breakers which stretched across it, and the next minute we were in smooth water under its lee.
"A cluster of bergs was seen to windward extending as far as the eye could discern, and so closely connected, that, except the small opening by which we had escaped, they appeared to form an unbroken continuous line; it seems, therefore, not at all improbable that the collision with the Terror was the means of our preservation, by forcing us backwards to the only practicable channel, instead of permitting us, as we were endeavouring, to run to the eastward, and become entangled in a labyrinth of heavy bergs, from which escape might have been impracticable, or perhaps impossible."
The Challenger, too, had uncomfortable experiences on February 24, 1874, when the late Professor Moseley relates "it blew a gale, with dry drifting snow obscuring the view and rendering it impossible to see for a greater distance than 200 or 300 yards." After having failed to fasten on under the lee of a berg, "either a back current set the ship on to the berg, or the berg itself was drifting towards us with the wind more rapidly than was expected. A collision ensued and the jibboom was forced against the side of the berg and broken, together with some parts of the rigging in connection with it. The end of the jibboom left a starlike mark on the sloping wall of the berg, but had no other effect on the mass. The men who were aloft reefing the topsails, came down the back stays helter-skelter, expecting the top-gallant masts to fall, but no further damage ensued.
"The weather became worse," continues Moseley; "we were in rather a critical position. We were surrounded by bergs, with the weather so thick with snow that we could not see more than a ship's length, and a heavy gale was blowing. The full power of steam available was employed. Once we had a narrow escape of running into a large berg, passing only just about 100 yards to leeward of it by making a stern-board, with all sails aback, and screwing full speed astern at the same time. The deck was covered with frozen powdery snow, and forward was coated with ice from the shipping of seas."
The following day the Challenger had forty icebergs in sight at noon.
At the end of March 1903, whilst looking for a harbour in the South Orkneys, we had four anxious days and nights on board the Scotia, navigating amongst bergs in dirty weather, and on the 22nd of March 1903 narrowly escaped shipwreck by collision with an iceberg. The nights at this time were very dark and of full twelve hours' duration, and it was blowing almost continually with fog and driving snow, especially when we came near the land. All day in such weather we would approach the land cautiously, looking in vain to find a safe harbour where the Scotia might winter; and at night, to prevent being driven ashore, we would steam out to sea. To the north of the South Orkneys at this time the sea was clear of pack ice, but it was full of bergs, and the greatest vigilance had to be shown. On the afternoon of Sunday, March the 22nd, while endeavouring to discover Lethewaite Strait, the squalls became exceedingly violent, accompanied by snow and very heavy, blinding drift from the high mountains of Coronation Island. Suddenly, there seemed to be a lull in the wind, and the sea became smooth as glass—an ominous sign, for we had assuredly come under the lee of a berg or high land. "Hard-a-port!" was Captain Robertson's swift order, and we swung round, and in doing so there loomed up on the port side the grim icy cliff of a huge berg, which almost grazed our yard-arms. Nothing but the able handling of the ship by my officers and crew, and their long experience of navigating among ice could have saved us from a most deadly collision, if not shipwreck: soon after, as the drift diminished, we sighted another berg to leeward, and a little later, when it cleared, we found we were completely surrounded by bergs.
Having dealt with Antarctic icebergs, let us now turn our attention to the other forms of ice I have mentioned. Apart from icebergs, all other Antarctic and indeed Polar ice is a product of the sea and not the land.