Evaluation of the Avalanche Danger in Northwest Rila Mountain - Sustainable Development in Mountain Regions: Southeastern Europe - page 97

Fig. 9.2 An avalanche cone on the left valley slope of the river Skakavitsa
The main ground surface forms which are formed by the activity of the
avalanches are the avalanche gullies, the avalanche rails and cones. The first two
types in their genesis are nival corrosion and gravitation forms, because they are
formed along the strongly declined slopes of the circuses and the glacial trough
valleys. Almost all avalanche gullies end in their mouths with an avalanche sedi-
ment under the form of an avalanche cone (Fig. 9.2 ; Peev, 1968 ; Peev and Dimitrov,
1971 ).
In the Northwest Rila Mountain can be seen one of the most specific avalanche
gullies in the whole mountain. Such can be seen at the circus of the Seven Lakes,
Urdinia Circus, under the southern edge of the Koupen Ridge to the valley of Rilska
River and the Meadow of Cyril—the location The Evil streams, the Alpine part of
the valley of the rivers Malyovitsa, Dupnishka Bistritsa, and Skakavitsa, the northern
slopes of the Kalinian part, the Otovishki circus, etc. (Figs. 9.2 and 9.3 ).
Avalanches are formed under certain climatic and geomorphologic conditions .
Almost all slopes in the Alpine part of Northwest Rila Mountain at the availability
of the relevant conditions can be avalanche dangerous. On some of them, the skiers
often do ski-dropping and snowboarding, which can be very dangerous.
The biggest and most dangerous avalanches are formed along the slopes with
declination between 25 and 45 ◦ (Mardirosyan, 2007 ). Very important are the
specifics of the snow coverage—its thickness, structure, and the peculiarities in its
distribution. The leeward slopes have a thicker snow coverage.
The mountain hostels located in the Alpine zone of Northwest Rila are “Ivan
Vazov”, “The Seven Lakes”, “The Rila Lakes”, “Skakavitsa”, and “Malyovitsa”