The duration of the snow cover was moderate; its average at 2500 ft. on the five representative mountain groups used as indices in these Reports was 79 days, which is about the mean of the previous five snow seasons.

Diagrams showing the distribution of snow cover relative to height for nine stations are given on pages 224 and 225.

In the Outer Hebrides some snow cover was reported from Harris in each month from October to May. The snow line fell to sea level on 13 days during the season, and the maximum duration of cover occurred in January with 25 days above 2000 ft. The Cuillins also had some cover in each month of the season, the summits down to 2000 ft. being under snow for the whole of January. The extreme summits were under continuous cover from December 20th to February 26th, and the snow line reached sea level on 27 days during the season, with a maximum of 16 days in January.

On the peaks bordering Glen Lyon the distribution of snow cover was similar to that on the Cuillins, with continuous cover on the summits from December 20th to February 22nd.

On Ben Nevis the extreme summit was under continuous cover from November 19th to May 2nd, a total of 166 days. The snow line reached sea level on 38 days during the season, with a maximum of 24 days in January.

Ben More, Isle of Mull, was free of snow during November at all levels and after February 18th only patches in gullies were observed. The snow line fell to sea level on 11 days, 9 of which were in January_; In the latter month at and above 2500 ft. snow cover was noted on 29 days.

Snow cover on the Paps of Jura was similar in distribution to that in Mull, none being observed after February 17th; in November only one day of cover was observed on the extreme summits. Snow cover lasted for 25 days in January at 2000 ft., but the snow line reached sea level only twice during the season.

In the Lake District, at High Close, Ambleside, no cover was observed in May, but the extreme summits were under snow throughout February and March. The snow line fell to 500 ft. on 25 days during the season with a maximum of 19 days in January.

The Caernarvonshire mountains had snow on the summits in each month from October to May, with a duration of 25 days and 28 days in January and February respectively.

The Brecon Beacons, as seen from Tairbull, had no cover in November or in May, but the summits above 2500 ft. were snow-clad during the whole of February, for 25 days in January and for 21 days in March.

Curves showing the total seasonal duration at six representative stations are drawn in Fig. 1, (p. 227). The maximum duration was that of 187 days on the summit of Ben Nevis. A total of 100 days’ cover was exceeded on the summits at all the stations except those in Wales, where 97 days were recorded on the summit of the Brecon Beacons (2907 ft.) against only 77 days on the summit of Snowdon (3560 ft.).

This was the first season since the Survey was resumed in 1946–47 in which the duration of cover on the Brecon Beacons and in the Lake District mountains has exceeded that on Snowdon as seen from Capel Curig.

Fig. 1

Fig. 2

Fig. 3