THE WEATHER

Thispart does not contain any scientific accounts of the meteorological observations undertaken by the expedition in King’s Bay, during the flight or during the twenty-four days’ stay in 87° 43′—this will be left for the scientific journals to publish. I shall only give here a characterization of the “polar-weather” as it was during 1925 and what was done in order to determine the best date for the start.

What kind of weather conditions must the flyers have for their journey towards the Pole?

First of all there must be no fog at the place where they have to land. Even if there is only a fog-belt extending a few meters above the ground, a landing is impossible and a “forced-landing” would almost certainly end in a catastrophe.

Further, the flyers must avoid passing through thick snow. The two flying-machines might easily lose sight of each other, and if, in order to keep in contact with each other, they should fly close together, there is always the danger of a collision.

An overcast sky without rainfall is also useless. At least it must clear now and again sufficiently to make it possible to navigate by the sun. It is of courseknown that steering by the magnetic compass is very uncertain so far north, as the extent of the deviations in the Arctic is not sufficiently known.

Luckily so much is known about the weather in the polar ice region that it is possible to choose in advance the most suitable time of year for a polar flight. First of all, Nansen’s expedition by the “Fram” in 1893–1896 has given us this knowledge about the polar weather. During almost the entire time of their drift across the Arctic observations were made nearly every two hours in the course of the day, so that a singularly rich stock of information exists. The observations have been thoroughly gone through by the late Professor H. Mohn, so that we have got them set out now in a most perspicuous form. Both the observers’ and Professor Mohn’s calculations are published in the work, “The Norwegian North Polar Expedition XVII Meteorology.”

THE TWO METEOROLOGISTS

N 25 ON THE WAY TO OSLO

I am going to cite some figures from this book which give a clear reply to the question, Which time of the year is the best for flying to the Pole?

In the three years which the drift lasted the approximate number of clear days per month were:

Thus in midwinter (December and January) nearly half of each month is composed of clear days, but the number quickly declines towards the summer and there are none in the four months from June to September. It happens, of course, that in the summer time the sun breaks through the sky at some time of the day, but eventhatis not very often. June had on an average twenty-six overcast days, July twenty-seven, August twenty-four, and September twenty-seven days.

ROUTE OF THE AMUNDSEN-ELLSWORTH FLIGHT

As might be expected, downpours are much more frequent in the gray summer months than in the other part of the year. The number of days with rainfall were, on an average, as follows:

Therefore one can count that two-thirds of all the days from May to September have rain or snow-falls. In the winter time, on the other hand, only one-third of the days have downpours.

Fog—the flyer’s worst enemy—also collects during the summer half of the year. Foggy days on an average were:

One is therefore pretty sure to be without fog until May, but from June to September it is general.First, in October the fog begins to get less and then disappears altogether in the middle of winter.

It appears quite clearly from the “Fram” observations that only the dark period of the year has somewhat stable weather conditions, with a clear sky. During the light period of the year the weather is gray and thick.

These conditions are as unfavorable as possible for all flying expeditions towards the Pole. The good weather during the winter—October to March—cannot be taken advantage of on account of the darkness, and it is necessary to be satisfied with the much more unfavorable weather during the lighter period of the year.

Luckily there is, however, an intermediate condition of weather, when the light is still there, but the summer’s gray weather has not yet set in properly. April with its eight clear weather days, seventeen days without downpours, and only one foggy day ought to offer the best conditions for flying. Only one has to remember that when flying over a longer distance the chances of getting into ugly weather are much greater than one would imagine from the impression given by the figures. In a distance of an extent equaling that from Spitzbergen to the Pole, during a good month such as April, one will in most cases have to pass through a bad and good weather-zone. In April, too, one has to reckon with severecold. “Fram” had a temperature as low as -38° 4 c. in the month of April and even at the end of that month it can go down to -29° c. If it is, therefore, one’s intention to fly on a day of good weather, it is necessary to be well protected against the severe cold.

In 1925 the polar flight could not be undertaken as early as April. Notwithstanding the fact that the journey from Norway was undertaken before the real opening of the shipping season, and that the preparations in King’s Bay proceeded quickly and according to program, our machines were not ready to start until the beginning of May. An earlier start might well have been possible if the previous winter had been spent in Spitzbergen.

It was the business of the meteorologists to determine which was the best day in the month of May for the start. With “Fram’s” experiences before us the prospects of finding a good starting day were not very rosy. In May, 1896, when “Fram” was about halfway between Spitzbergen and the Pole, there were twenty-five days with rainfall, and only three days at the beginning of the month had clear weather. Should May, 1925, turn out just as bad as May, 1896, the polar flight would take place under very risky meteorological conditions.

What resources were now at our disposal to determine what kind of weather was expected? First werethe telegrams from the stations in the neighborhood, indicating the kind of weather which was approaching. This system is commonly used by all meteorological institutions which have something to do with weather reports, and it was therefore only natural that this should be made use of for the polar flight. One can, however, know beforehand that to make weather forecasts at Spitzbergen is much more difficult than at other places where it has been tried before. For instance, Southern Europe is covered by a network of telegraph stations which can report the approaching weather. But in Spitzbergen it is not so easy. The network of European stations certainly give reports of every condition approaching from the south, but no telegraphic weather reports can be obtained from the west, north, or east. There are, therefore, many situations where the meteorologists, notwithstanding all the aid, can give no reply to the question: “What will the weather be like to-morrow?”

And that is the case in Spitzbergen. But the polar flight had to be undertaken from there, and had to extend more than 1,000 kilometers above unknown regions in unknown weather conditions! How could any one guarantee good weather for the whole distance?

I know that many meteorologists would reply to such a question that this is beyond science. To prophesywhat the weather will be like near the Pole is pure guesswork. As now and again stress has been put upon this view in the press, may I be permitted to defend the foolhardiness I showed by venturing to tackle this problem? I admit that it is very often quite impossible to say what the weather will be like on the way from Spitzbergen to the Pole, and still less possible to predict how it is likely to turn out in a day or two’s time. But meteorology allows us to determine by indirect conclusions whether the prospects of good weather are bright or whether the situation is too risky. That these weather forecasts are based on very weak foundations, and therefore can easily turn out wrong, was known by the airmen from the first hour. Still they preferred to follow the advice science could give, even if it was often vaguely formulated and given with all sorts of provisos.

The plan was not to risk a flight in any case through fog and thick snow, where the aeroplanes would certainly lose sight of each other, but to turn back if the weather should begin to look too threatening. It would then be the meteorologists’ problem to find another occasion when it would be again worth while to try and see whether in a renewed attempt the way to the Pole would be clear.

For several years the exchange of meteorological weather reports had been broadcast by wirelessso that everybody who had a receiving apparatus could make free use of the same. “Fram’s” receiving apparatus was of the latest type and worked very well, even receiving meteorological messages from countries very far distant. Mr. Devoid attended to the receiving of nearly all the weather reports—a job he was well acquainted with, through his position as assistant at the Geophysical Institute at Tromsö. It can safely be said that we could not have got a better man for the handling of all the radio weather news which came to hand. He was untiring in trying to pick up and read communications which were very weak, coming from far distant stations, and it was, thanks to him, that the weather forecasting station at King’s Bay was able to work with nearly the same full range of meteorological observations as any southern weather forecasting station.

The meteorological despatches are broadcast by international agreement and, with one single apparatus, one can receive accounts of observations from the whole of Europe, North America and North Asia. That has been made possible by the various countries all having come to an agreement, in which they have arranged to send despatches following each other closely according to a prearranged time-table. On the “Fram” we regularly received the following despatches:

As will be observed Mr. Devold had a lengthy time-table each day—Sunday as well as week day. The despatches which arrived during the night and the early morning were received by the ship’s own operators, who besides had, as part of their duty, to attend to the expedition’s very large press correspondence when not attending to the meteorological telegrams.

Nearly all the north, west and middle European states are represented in the list. Observations from those countries, the despatch stations of which one could not hear direct (for instance certain south and east European), were received indirectly through the “collected messages” from London and Paris, which give extracts of all the observations from the whole of Europe.

Special mention should be given to the despatches which were sent out specially for the expedition. First come the extra observations which the U. S. A.started broadcasting from Alaska, Canada, and the United States. These formed a very important addition to the general meteorological observations which America usually sent out for European use. It was especially important for us to get the complete observations from Alaska—the nearest inhabited land—on the other side of the Pole. The whole of this extensive observation material was supplied gratis by the United States of America Weather Bureau, and telegraphed free of charge by the U. S. A. Naval Station, Annapolis. It gives me great pleasure to mention the tremendous assistance which the United States gave us in this connection, and I herewith offer them the expedition’s grateful thanks.

Despatches from Annapolis were received by the Stavanger station, which repeated them to the “Fram.” This was also done free of charge. The Norwegian telegraph authorities also showed their goodwill to the expedition by instructing Vardeo Radio Station to receive despatches from North Russian and North Siberian stations and repeat same to the “Fram,” which hardly could have got them direct. I must also mention the help the radio station in Green Harbour gave us by assisting in receiving messages and forecasts during the critical days just before the start.

The Geophysical Institute at Tromsö, which is the central station for the weather-forecastings for NorthNorway, sent from its radio station, three times daily, the Norwegian observation material.

The institute in Tromsö also deserves thanks for all the assistance it has given to the expedition by sending out weather forecasts from the moment the trip was planned, and whilst we made our preparations in the winter 1924–5. It was a great help to be able to sometimes consult the nearest meteorological neighbors in the south, who had many years’ experience in the Arctic Sea’s meteorological readings. I will specially mention a telegram we received from Director Krogness a few days before the start which informed us that his analysis suggested that a period ofstableweather conditions was now approaching. This was of great assistance when the starting day had to be fixed.

When the whole apparatus was in working order we could receive meteorological despatches from nearly all the stations. The network of stations is closest in Europe, so close that we often saved work by making a choice of stations. Asia and America have not such a close net, but even here it is possible to draw a weather chart which is largely correct.

THE COURSE OF THE SHIPS ON WATCH, “FRAM” AND “HOBBY,” DURING THE COURSE OF THE EXPEDITIONThe dotted area indicates the pack ice.

THE COURSE OF THE SHIPS ON WATCH, “FRAM” AND “HOBBY,” DURING THE COURSE OF THE EXPEDITION

The dotted area indicates the pack ice.

Furthermore, in the English, French and Norwegian despatches there were a certain number of observations from ships in the Atlantic, which in themselves formed a bridge between the American and European stations. The whole station system thereforeformed an almost complete circle round the polar regions, with the exception of Northeast Siberia, where telegraphic communications are still bad, and this of course makes a wide gap.

THE DOTTED AREA, ABOUT 12,000 SQUARE MILES, SHOWS THE TERRITORY EXPLORED BY THE FLIGHT EXPEDITION

The point now was (with the assistance of this net of stations round the Arctic regions) to control an account of conditions moving inside the polar area, and thereby draw conclusions as to what the weather might be like along the flight route. With this in view the weather chart for the whole region was drawn twice a day. Besides this, two charts were prepared daily showing the reports of the European net of stations, so that the weather conditions were being calculated every six hours.

The drawing up of the weather charts took place in one of “Fram’s” afterholds, which (with this end in view) had been prepared as a “weather forecast salon.” There was not overmuch room for all the charts, instruments and other apparatus which had to be kept there, especially as the hold also served the purpose of an office for Dr. Matheson, the expedition’s doctor. But with goodwill from both sides it worked smoothly the whole time, combining the weather forecasting with the doctor’s practice in the same room.

After the weather forecasting was properly established I often had the pleasure of receiving visits from the members of the expedition who were housedon land. During the quiet periods when nothing special was being accomplished, our two journalists were frequent visitors. In lieu of something better to do, they wrote about the weather, simply because it is always possible to say something regarding this subject. As the time for starting approached, Captain Amundsen and the other polar flyers often visited me in order to see what the prospects were. During the times that “Fram” was not lying in safe harborage Captain Hagerup was constantly in communication with the weather-forecasting station in order to ascertain in good time whether wind was approaching which might drive the drift-ice towards us. On the whole I could not complain about the amount of faith that was placed in the weather forecasts, but it was often necessary to reduce this trust by reminding every one how little we really knew.

All the outside observations were made by the meteorologist, Calwagen, Manager of the Meteorological Observatory in Bergen. His duties were so numerous that they deserve a whole chapter in this report, but as it has so far been impossible to make any preparation of the observations, Mr. Calwagen’s calculations must be reserved for later publication in scientific journals. With Mr. Calwagen’s permission I shall only mention here that part of his activity which was of direct use in the weather forecasts.

In order that nothing which happened concerning the weather conditions should pass us unnoticed, Mr. Calwagen made observations as far as possible each hour of the day, continuing until late at night. These observations included wind, sky, cloud movements, cloud structure, cloud altitude, rainfall, atmospheric visibility, atmospheric temperature and dampness, the readings of the barometer, etc. Further we had brought with us a case of self-registering instruments for measuring the atmospheric temperature and the dampness. Inside were two barographs—one in the ship’s instruments’ compartment, and one in the weather-forecast compartment, which both gave information about the changes in the air pressure.

As often as we got rid of the low clouds, Mr. Calwagen sent up the pilot balloons for observing the wind’s direction and strength. These observations were of the greatest value for judging the weather conditions, and I will therefore mention them in a few words here. The observations took place as follows: A colored rubber balloon is filled with water gas until it is one-half meter in diameter. One weighs its buoyancy and thereby knows the speed with which it will rise into the air. After the balloon has been sent up it is observed through glasses which have graduated scales for calculating necessary horizontal and vertical adjustments—this is called a theodolite.The theodolite’s indications are read and noted each half minute whilst the balloon rises. Afterwards it is possible to reconstruct the course which the balloon has followed, and to ascertain hereby the course of the wind at the different heights.

It was not always easy to find a suitable place to set up the theodolite. On board the “Fram” it very often happened that the balloon after some minutes got behind the ship’s masts or funnel, and thereby was lost from view. On the ice in the fjord it was generally possible to find a good spot with the exception of the days when there was a heavy swell on the water outside, which also set the fjord ice making slight undulating movements, and which were disturbing enough when it was a question of reading one-tenth of a degree on the theodolite. Near Danskeöen, where there was no useful fjord ice, Mr. Calwagen had to be rowed ashore for each pilot observation in order to have firm ground below the theodolite. Generally he chose the little islet “Likholmen,” where he could sit and have an uninterrupted view on all sides. When the “Fram” went out to get fresh water-ice from an iceberg which had got aground, Mr. Calwagen was there immediately and set his apparatus up on the iceberg. This is probably the first time that pilot balloon observations have been made from an iceberg.

With the execution of all these pilot balloon observations, under conditions which were continuallychanging and often difficult,*Mr. Calwagen had to use all his care and all his skill. It can certainly be said that he made use of every possibility imaginable in order to collect data which might be helpful in supplementing the expedition’s weather forecasts.

*After having sent in this report, the sad news had just been received that Mr. Calwagen has been killed in a flying accident at Kjeller, near Oslo, on the 10th of August, 1925. Immediately after arriving home from Spitzbergen he commenced to work on that branch which he was the first to start in Norway, namely, the reading of the atmospheric conditions by self-registering instruments installed in aeroplanes. In the course of the last year he has personally taken part in many flights in order to complete the registering-dials of the instruments from his own observations. The accident happened during such a flight, just when he was engaged in collecting observations for determining the atmospheric belts.All who were with the expedition will no doubt remember Mr. Calwagen as a practical man, helpful, impulsive, bubbling over with merriment, capable but at the same time possessed of a modesty which was the natural result of his noble altruistic nature. We all feel very grieved at such a man’s death.

All who were with the expedition will no doubt remember Mr. Calwagen as a practical man, helpful, impulsive, bubbling over with merriment, capable but at the same time possessed of a modesty which was the natural result of his noble altruistic nature. We all feel very grieved at such a man’s death.

When it was necessary to have two men for the pilot balloon ascents, Mr. Calwagen got excellent assistance from ice-pilot Ness, who, according to what he himself said, was only too glad to be employed a little on such an occupation during the long hours in which “Fram” lay idle, not giving him enough to do.

Altogether sixty-two pilot balloons were sent up between the 15th of April and the 29th of May. It was possible to follow one of them through glasses to a height of 10,500 meters. This, however, was only possible because there was very little wind all the way up. Generally the wind was so strong that the balloon was lost sight of at a much lower height.

It will lead us too far into scientific spheres to describe all the methods used in determining the weather conditions from weather-charts and from observations which were made. I shall have to content myself by just mentioning the main principles which must be taken into consideration when choosing the starting day.

It is the general experience that the regions which have low air pressure mostly have cloudy weather and rainfall, whilst places with high air pressure have fine weather with a clear sky. The point was therefore to avoid conditions where a depression was moving towards the Pole.

In order to be pretty safe from bad weather it was necessary to choose a high pressure condition. Further, the high pressure would have to lie north of Spitzbergen so that the aeroplanes should not fly out of good weather directly into bad on the way north. A high pressure condition over the Pole would necessarily bring with it northeasterly winds and cold weather in Spitzbergen. This northeasterly wind would (at West Spitzbergen) be an off-shore wind and therefore would signify clear weather. Along the north coast of Spitzbergen the weather would be more doubtful, with a northeast wind which would cause the air to rise up against the hills and form clouds. But these cloud-masses on the north coast would very often only stretch out over a limited areawhich the flyers could pass in a short time, preferably by flying over the clouds.

One has the best guarantee for stable weather conditions when the pilot balloons show that northeast winds are not only to be found on the ground but also higher up. One knows then that the high pressure condition around the Pole will reach high up in the atmosphere and is not just a low formation which could be swept away by the first attack of a storm center from elsewhere.

The first high pressure condition in May occurred on the 4th, just when the aeroplanes were finished mounting. This favorable condition did not last long. The low pressure over North Norway increased and passed northeast (along the dotted line on the chart) by pushing the polar high pressure aside towards Greenland. Before the final preparations were finished on the 8th of May the low pressure had got so near the Pole that it was not advisable to start.

A period of drizzly weather followed now when it was impossible to do anything else but wait. The wind was mostly between west and south, and the sky was overcast and we often had snow showers. Only now and again it cleared for half a day, but never long enough that there could be a question of starting. This state of affairs lasted until the 18th of May, when a change took place. A heavy storm center, which passed Björnöya, turned the wind easterlyat Spitzbergen, and behind the bad weather a high pressure region appeared which moved from Labrador via Greenland towards the Pole. The wind was still too strong, and it was not quite clear at Spitzbergen, but there were good prospects that the next few days would bring good weather conditions for the flight. The planes were therefore made ready to start at short notice.

We had still to wait three days before the weather was as it ought to be. The high pressure region had spread itself long ago over the Arctic Sea, and the bad weather which passed Björnöya had moved to North Siberia, but right up to the morning of the 21st we had dull weather with snow now and again in King’s Bay. The reason was a slight local depression which had remained persistently over the warm current which the Gulf Stream sends along the west coast of Spitzbergen. On the 21st there was, for the first time, sufficient easterly wind to drive the snowy weather out to sea, so that from midday on we had radiant sunshine and a cloudless sky.

At last the condition had arrived for which we had waited so long, the first useful condition since the planes had been ready to start. Ithadto be used, especially as the season was getting on towards the end of May and the danger of fog was increasing each day.

So far we had not seen any fog at Spitzbergen andif one had not had the knowledge about polar fogs which “Fram’s” observations, 1893–6, had given us, it would have been tempting enough to wait longer. It was still pretty cold, -9° c. in King’s Bay on the 21st of May and at the Pole one might risk calculating that the temperature would be down to -15° c. Both for the planes and the crews it would have been better and more comfortable to have had a more summery temperature. But of two evils choose the lesser. As soon as the summer arrives in North Europe, North Siberia, Alaska and North Canada, fog starts to reign over the polar sea. Each air current above the Arctic, no matter from which direction it comes, will bring with it warm air, which is exposed to a lowering of the temperature on contact with the polar ice. This cooling of the warm air which contains a great deal of dampness causes fog. This formation takes place quite independently regardless of whether there is high or low pressure. Even the best high pressure condition in the summer, might therefore be useless for flying. During the high pressure one will certainly be free from the clouds which produce snow and rain, and the flight can take place in radiant sunshine, but fog, even if it only reaches twenty meters up from the ground, will make a landing impossible.

Fog of that kind was very unlikely on the 21st, in fact, one might say the possibility of its existence wasquite excluded. The northeast wind on that day was so cold (-9° c.) that it must have come from the very central regions of the polar ice, and it is hardly probable that on its way to Spitzbergen it should have been exposed to the further lowering of temperature, which would have been necessary to produce fog.

All these observations led to the following result: “Conditions to-day are as favorable as can be expected so late in the summer. It was not without nervousness that I advised the airmen of this result on the morning of the 21st—never have I given a weather forecast with such a heavy sense of responsibility. It was almost weighing me down with its fateful importance, but on the other hand it was bracing to note how the airmen arrived at theirmuch more responsibledecision: “We start to-day.”

And it was so! The last reports which were received at midday did not show any change for the worse, so there was not the slightest reason for calling off the start. The sky grew clearer continually; Mr. Calwagen had the opportunity of following the ascension of a pilot balloon with binoculars to a height of 4,000 meters. It showed a northeasterly wind, apart from the lowest belt, where the wind blew southeast from King’s Bay. The northeast wind high up had a speed of between eighteen to twenty kilometers per hour. Therefore if this strength should continue throughout the eight hoursof the flight towards the Pole, it would give the planes a deviation of 130–160 kilometers. So much petrol was to be kept in reserve that the last stretch could also be flown, especially if one could reckon on the wind beingwiththe planes throughout the flight homeward. Mr. Calwagen wrote down the results of the pilot’s calculations and handed them over to Captain Amundsen to assist him in the work of navigation.

Herewith the task of the meteorologists was ended, and in the last unforgettable minutes we all stood as spectators, filled with admiration for the six brave men who smilingly said good-by as if they were just going on an everyday flying-trip. Not long afterwards both machines were out of sight in the bright blue sky flying in the direction of Cape Mitra.

* * * * *

Forty-five days later the polar flyers are home in Oslo again and Captain Amundsen and Ellsworth’s meteorological notes are handed over to us. We read them through with excitement. They contain news from that part of the world which otherwise is out of the meteorologists reach. They give him something to think about—especially after he has dared to predict what kind of weather the polar flyers were likely to meet in the unknown.

We start with the reports referring to the very beginning of the flight from King’s Bay and see what the meteorological notes tell us.

After flying along the coast and passing the seven glaciers, the flyers find Danskeöen’s and Amsterdamöen’s hills enveloped in fog which continues northwards as far as the eye can see. What can this have been caused by?

I cannot judge by personal examination because when twelve hours later we ourselves arrived up at Danskeöen on board the “Fram” there was not a sign of fog to be seen. But I am inclined to believe that the fog has been composed of a layer of certain low-lying clouds, which had often been seen by us at the beginning of May while we were lying in Syd Gat waiting for suitable weather for the expedition’s start. These clouds will often just form suddenly when a cold wind blows from the polar ice towards the open sea. The moment the air arrives over the first water-lanes or open sea it gets heated from below. The heated layer rises above and whilst ascending forms clouds. Other colder parts of the air then come into contact with the water, get heated and rise also forming clouds, etc. According to the observations which we had occasion to make at Danskeöen in the beginning of May, the lower surface of these clouds is about 200 meters from the ground. Below this there is generally a thick mist of fine snow which reduces atmospheric visibility and will certainly be very disturbing for flying. Luckily these clouds do not reach to any great height, seldom over 1,000 meters, so thatone can easily fly above them. Besides, one can count on their not forming further north than where one finds open water channels of fairly large dimensions. It is therefore nottoorisky to undertake a flight above the cloud-belt towards clearer weather farther north.

The polar flyers took this risk, and quite rightly too. After two hours’ flight from Danskeöen going northwards there were no clouds, and on the remainder of the flight there was nothing that obscured the view over the polar ice.

The expedition has here made a meteorological reconnaissance of great importance to all later flying explorations in the Arctic.

If a cold wind blows from the Pole one must reckon with the formation of a low cloud belt over the wider water channels, even if it is cloudless nearer the Pole. These clouds will form at all seasons of the year, but perhaps mostly in the colder periods, when the difference in temperature between ice and sea is greatest.

The landing took place in a light wind, therefore probably near to the center of the high pressure region, which covers the Arctic Sea. On the way into the high pressure region the wind, however, must have been considerably stronger as is shown by the very considerable deviation of 250 kilometers on an eight hours’ flight. In the middle period of the flight it musttherefore have been thirty kilometers per hour, which is considerably more than the pilot observations over King’s Bay had shown, namely, twenty kilometers per hour. The aeroplanes must have flown, therefore, through a zone with strong northeasterly winds blowing north of Spitzbergen, and then later come into calmer wind conditions nearer the Pole.

This raises the question: Could one not have found a day with a gentler wind blowing, when the deviation would have been less and the Pole might have been reached? Probably the next day, 22nd of May, would have been better as far as wind was concerned. Mr. Calwagen measured the speed that day at Danskeöen, finding an east wind blowing three kilometers per hour at a height of 500 meters. This wind would only have brought a deviation of about 100 kilometers. But according to Amundsen’s observation reports there was, on the same day, a little northerly breeze at the landing place at 87° 43′, which means that a contrary wind was also blowing on that day over the district nearest to the Pole. And what was worse, on the 22nd May there was no longer clear weather near the Pole.

The observations were as follows: During the last two hours of the flight slight high clouds had begun to appear, but not so dense that they could prevent the taking of solar observations immediately after landing. The next day the clear weather was goneand solid gray cloud layers covered the whole sky. It was the polar summer weather which had started, just as we calculated it would from the “Fram” expedition’s observations. And it did not improve during the following days; the 23rd, 24th and 25th were all gray-weather days, certainly without rainfall, but also without sunshine. A northerly breeze was blowing on the 22nd, 23rd and 24th, but it got calmer on the 25th.

The big high-pressure region which we had over the Arctic Sea on the starting day continued, and the polar flyers must have been very near the high pressure center as they now had calm weather. As far as could be seen everything looked favorable, and whilst we were lying and waiting at Danskeöen in radiant sunshine, the whole day long, I personally thought that this good weather would certainly stretch right up to the Pole. But here the expedition’s observations have taught us something else, that in the best of weather conditions there is gray weather at the Pole when the year is so far advanced as the end of May. This is also one of the new meteorological results which this expedition has brought to light—in regard to the “Fram’s” expedition it happened that they did not meet any high pressure regions at the end of May.

There were a few occasions when the clouds broke up at 87° 42′; for instance, the 29th of May “dawned with sunshine from an almost quite clearsky.” But this was only a sign that worse weather was approaching. In the night, between the 28th and 29th, snow had passed Spitzbergen on the way north. It reached the polar flyers on the 30th in their camp 87° 43′. The clearing on the 29th was therefore just a passing phenomenon, and if the aeroplanes had started that day southwards they would after a few hours’ flight have got right into a heavy snowfall. These clearings, before the large wandering snow-masses, are well known in lower latitudes. It is, however, interesting for meteorologists to find that the same rules also apply to the weather conditions at the Pole.

Now follows a period of prevailing southerly and southeasterly winds which cause the temperature to rise quickly. On the coldest day, the 24th of May, there had been -12.5° c., but at the end of the month we already had +7° c. and on the 7th of June the temperature was up to 0°. This enormously quick change from winter to “summer temperature” is typical of the polar conditions.

“Spring” does not last “month’s,” as in the lower latitudes—it is finished in a few weeks’ time.

From the 7th of June onwards the temperature did not rise much; it remained about 0°. Sometimes a little over, sometimes a little under. One can say that 0° is the characteristic summer temperature of the Arctic region. Warmer air than 0° is very often carriedthere from lower latitudes, but this gets cooled down immediately through contact with the ice, and gets a temperature of about 0°. As mentioned before, it is this cooling down which is responsible for the fog because it causes the air’s moisture to condense. The first fog, which extended right down to the ground, was observed on the 2nd of June; the next was on the 8th of June, and thereafter happened fairly often, so in the end whole days free of fog were exceptions.

Luckily on the 15th of June, when the starting place was ready, there was sufficient visibility for them to start and to find their way out of their “Foggy” home.

THE END

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