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In contrast to temperatures, which are important for the survival of the glacier above all in the ablation season, the total amount and the form of precipitations are important all year round. Therefore the table below comprises data for all months (acc. to the source: Klimatografija, 1989; Archives; solar energy - acc. to Hočevar et al., 1982).

The smaller annual amount of precipitations at Kredarica than at the lower South margin of the Julian Alps is interpreted by certain authors: due to the wind, not all precipitations are caught in rain gauge. The proof that this circumstance does not essentially reduce the annual sum is offered by the annual amount of precipitations measured on the profile ex- tending from the southern edge to the highest, i.e. central part of the Julian Alps. On the north-facing slope of the Bukovske gore (i.e. mountains south of Bohinj) totalizators collected over 3500 mm, 2393 mm at Komna (altitude - 1520 m, 1931-60 period), at the basin station of Stara Fužina 2332 mm (1961-90 period), at Mrzli studenec on Pokljuka 2122 mm (1931-60 period), and 1996 mm at Kredarica. Precipitations decrease northwards irrespective of the altitude of the station. The same can be seen in the valley of Trenta: Lepena - 3077 mm (altitude - 480 m, 1951-80 period), the source of the Soča - 2383 mm (880 m).

But it is questionable whether the same precipitation conditions as registered at the Kredarica station apply to the glacier. The majority of precipitations fall in cyclonic weather conditions with increased windiness. Due to the NNW-SSE direction of the Triglav crest the prevailing west winds change their direction. Southwest wind rounds Mali Triglav and blows across Kredarica as SE wind; over one fifth of annual winds belong to this direction, with the maximum in October and November. The west wind rounds the crest on the north side and blows across Kredarica as NW wind; to the latter, over one third of all winds belong, 4 1 % of them in winter. But the glacier's location is partly in the lee of these winds, particularly behind the crest of Veliki Triglav towards the Kugy shelf (Kugyjeva polica). But this location gets greater quantities of rain at-id particularly of snow. Due to its location, the meteorologic station registered very low frequency of south wind which supposedly prevails in baric depressions when cold fronts pass, since the Julian Alps receive the majority of precipitations on the southern margin which runs in the W-E direction. And as to these winds, the glacier is even more expressedly in the lee.

 

Table 3 - Precipitations, wind and insolation energy (1951-80).

Month

1

2

3

4

5

6

Total monthly precipitation in mm

104

98

124

152

169

214

No. of days with >0.1 mm of precip.

10

10

12

14

15

16

No. of days with >0.1 mm of rain

0

0

0

1

7

14

No. of days with snow cover at 7 a.m.

31

28

31

30

31

25

Maximum depth of snow cover in cm

434

521

588

690

630

422

Relative moisture in %

71

73

77

83

84

83

Calms, %

14

15

14

19

20

22

Days with winds of  8 Beaufort

11

7

8

5

4

3

SE wind frequency, %

19

22

18

24

26

22

NW wind frequency, %

41

40

39

32

30

33

Insolation energy in kWh/m2

42

56

92

109

138

135

 

Month

7

8

9

10

11

12

1-12

Total monthly precipitation in mm

204

227

197

187

204

12

1995

No. of days with >0.1 mm of precip.

14

3

10

9

11

10

136

No. of days with >0.1 mm of rain

15

13

9

6

2

0

68

No. of days with snow cover at 7 a.m.

8

2

6

16

26

31

262

Maximum depth of snow cover in cm

438

30

95

198

254

310

690

Relative moisture in %

81

81

76

70

71

69

77

Calms, %

23

26

23

21

15

14

19

Days with winds of  8 Beaufort

3

2

3

5

9

11

73

SE wind frequency, %

21

24

22

27

24

20

22

NW wind frequency, %

37

33

36

33

37

43

36

Insolation energy in kWh/m2

133

114

99

79

43

35

1074

Note: Since tenths have been omitted, the annual amount does not equal the sum of individual months.

The maximum depth of snow cover at Kredarica increases, after the minimum in August, to 95 cm in September, and almost 2 m in October. Then follows a gradual increase until April (690 cm). In May, it already declines by 60 cm, but it declines most in August when it is by 408 cm thinner than in July. Thus, the majority of snow and ice melt in the month which is, as to the number of solar hours, already poorer than July. Yet, August surpasses July in the number of calms, since in August their number is the greatest in the whole year. It is the result of anticyclonic weather conditions which are most frequent in this month.

Out of 68 days with rain (0.1 mm or more), 42 (or 62%) belong to summer months. There are still more days with snow falls than rain in May, which is, again, the result of the dropping temperatures at cyclonic weather. Notwithstanding this, the increased radiation and longer insolation of the glacier reduce the maximum depth of snow cover. These are the averages. In 1956, the snow cover was deepest in June, but the next year, it was in January.

In the 1961-90 period, the snow cover, measured at 7 a.m. at the station, lasted all days in winter and spring months, and as follows: 25 days in June, 7 days in July, 1.6 days in August, 6 days in September, and 25 days in October. However, snow remains longer on the glacier.

In 136 precipitation days, the Kredarica station annually gets 1996 mm of precipitations, or 22 mm/day on the average. If the same is true of snow precipitations (131 days of snow failing), there would be 288 mm of water. Since average temperature in the accumulation season amounts to -5.50C, dry snow prevails with the density of approx. 0.15. On this basis, the estimation is made of about 8.7 m high annual snow precipitations. Besides, the snow which slides from the surrounding slopes also accumulates on the glacier.

According to the above mentioned Finžgar's sketch of the glacier's shadiness (Meze, 1955, attachment 1), the north-facing slope of the Mali Triglav-Veliki Triglav ridge and the crest running towards the Kugy shelf comprises about 44% of the glacier (of the area from the end of the 1940's, i.e. 12 hectares). Due to the inclination of this slope, about 301, which approaches the angle at which the uncompacted dry snow slides down, it is understandable that meteorologic surveyors from Kredarica, when making reports on the glacier, and other people, too, reported about the sliding of snow from the surrounding slopes, and avalanches sliding on the glacier (see Meze, 1955; Šifrer, 1963, 1976, 1986), even, such ones that prolonged their way further on (Meze, 1955), but the latter are very rare. Only on a moderately inclined shelf below Veliki Triglav peak, more permanent snow can be retained all year round at this altitude of 2700 m. This is the so called Upper Snowfield which disappeared only once in the period surveyed.

Most probably, the amount of accumulated snow on the glacier is by one third greater on account of the sliding snow from the surrounding slopes. Therefore, the snow in the upper edge of the glacier in spring elevates in the form of snow fans in the furrows of the slopes where sliding snow is accumulated.

 

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