Grfmsvötn (The Lakes of Grünur) is the name of a volcanic centre in Vatnajökull, the eruptions of which accompany the gigantic glacier bursts on Skeidarársandur which occur normally about every tenth year. Recent expeditions to Grimsvötn and reconnoitring flights have led to the view that between glacier bursts the Grlmsvötn depression is gradually filled with water, forming a lake with a maximum area of about 35–40 sq. km. This accumulation of water is partly due to ablation and partly to continuous solfatara and fumarolic activity.

The close resemblance between the discharge graphs of glacier bursts from Grimsvötn and graphs of drainage of normal ice-dammed lakes such as Lake Graenalón is stressed. It is also pointed out that ten years’ accumulation, about 7 cu. km., in the area drained into the Grfmsvötn depression, corresponds roughly with the total discharge of a normal glacier burst from Grfmavötn. It is suggested that the glacier bursts determine the moment of eruption and not vice versa. This might explain the usually very regular intervals between these eruptions. The irregularities occurring since 1934 might be due to the present climatic amelioration.

Accumulation and ablation measurements on Morsárjökull are described and a tentative glacier budget for the three seasons 1951–52, 1952–53 and 1953–54 is presented. Observations of glacier flow on Morsárjökull, Svinafellsjökull and Skaftafellsjökull are considered. The recent fluctuations of the snouts of Skaftafellsjökull and Svinafellsjökull are discussed and related to variations in the height of the accumulation zones of the glaciers; recent glacier thinning is also mentioned.

A summary of the winter conditions at the edge of the pack ice around Antarctica, as observed on 16 occasions by the R.R.S. Discovery II between 1932 and 1951, is followed by a more detailed account of each visit. The state of the ice on the northern fringe of the pack is noted especially with reference to the various stages in the formation of pack ice. Detailed reference is also made on each occasion to the meteorological conditions obtaining not only during the ship’s stay on the ice edge but for 2 or 3 days beforehand. Despite the limited number of observations possible it would appear that the state or condition of the ice edge, at any one point in winter, is Iargely dependent on local weather conditions, and it is suggested that, basically, the condition of the ice edge falls into three or, possibly four main categories.

Attention is drawn to the possible relationship between the sea surface temperature and the condition of the ice on the fringe of the pack but it is considered probable that the surface temperature has a greater effect on the distribution of pack ice generally, rather than on the state of the ice edge locally.

This report is of a preliminary nature; detailed analyses are being carried on at the present time. The tunnel project on a small cirque glacier in the Jotunheim area of Norway, made possible observations of englacial movements in August and December of 1951 which are correlated with surface movements. Emphasis was placed on detailed three-dimensional studies. A marked divergence of flow lines was noted in both the vertical and horizontal planes. Bands previously thought to be thrust planes were found to be of sedimentary origin and not to be discrete planes of shear. Rates of contractions of tunnel sections up to a depth of 50 m. were observed and the englacial temperature distributions were taken in both zones of ablation and accumulation.

Penitents are observed on all the snow fields and glaciers of the Santiago Andes between 4000 and 5200 m. They are caused by the prolonged action of the sun in a dry and cold atmosphere, The sublimation of the snow or ice allows the crests to maintain their temperature below 0° C., while in the spaces or passages between the penitents, where radiation is concentrated and removal of water vapour not so easy, melting takes place. This hypothesis is justified by a brief study of the climate of the high Cordillera of Santiago; this study has been attempted for the first time with the help of meteorological information obtained from La Cumbre (3837 m.).

The first stage of the penitents is a form of “micropenitent,” similar to that observed at the end of the winter below 3500 m. These micropenitents frequently come from crusted snow which has cracked. The compact ice penitents are directly formed from ice, as is proved by the existence of ice micropenitents.

The firn field on the volcano Popocatépetl is most extensive, lowest in altitude (4573 m.) and thickest (40 m.) on the northwest side of the cone. An expansion of the firn field on this side in the form of two small glaciers, one with miniature lateral moraines, has appeared since 1945 and still persists. Crevasses in the firn appear, widen, progress downslope and disappear, with new ones replacing them from above. Accumulation of snow from November through January and also from June through September exceeds ablation, and permits development of the firn field with expected seasonal and annual marginal fluctuations. A recession of 100 m. in altitude of the firn field from 1906 to 1920 is indicated by photographic studies and by field evidence.

Information concerning the supply area of Morsárjökull, a small outlet glacier of Vatnajökull, was derived from a firn profile measured in a pit 6 m. deep.

The conspicuous bulge on the medial moraine is, by extrapolation from the annual movement, attributed to a former glacial recession between 1890 and 1900. This bulge is correlated with discontinuous moraines near the head of Skeidarárjökull.

Moraines indicating a former greater extension of the glacier are mentioned and evidence showing the recent rapid retreat and thinning of the glacier is presented.

The structure of some moraines in and around two glaciers in northern Norway was studied by the method of fabric analysis. It was found that englacial material tends to lie parallel to the direction of movement of the ice, and material in lateral and terminal moraines shows orientations which appear to be related to the conditions under which it was deposited.

Three valley glaciers of the eastern Alaska Range are described. On one of these, the Castner Glacier, an unusual medial moraine was discovered, which has its beginning from an outcrop in the center of a cirque-like basin. This large moraine extends down the glacier for 4 miles (6.4 km.) and ends abruptly several miles from the end of the glacier. The advances and recessional behavior as deduced from end moraines, lateral moraines and the limits of forest destruction (forest trimlines) are briefly discussed.