Rila Monastery Nature Park Management Plan - part - usaid

February 2004
2.1.6 The wind factor
The wind direction and force are largely dependent on the lay of the land.
Wind direction and humidity transfer
It is an established fact that the prevailing wind direction in the territory of RMNP is
from the south-southwest to the northeast. Air currents are largely formed under a
Mediterranean and, in part, Atlantic influence. The average wind speed at 2,000m asl
is 8-10 m/sec., reaching 16 m/sec. (ca. 60 km/h.) about 30% of the time. In the lower
altitudes wind speed never exceeds 4-9 m/sec. The night-time wind circulation is
within the 1-2 m/sec. limit. Owing to the fact that the lower Park zone is drier, there is
no vertical humidity transfer in the direction of the higher altitudes.
Windfalls
As was noted earlier, the area of RMNP is characterized by temperature inversions
which generate descending wind currents sliding down slopes at relatively high speed
(20-30 m/sec.), but within a limited range. No specific pattern has been found in the
dynamics of stormy winds of the kind that causes windfalls.
2.2 Geology and geomorphology
2.2.1 Geological and tectonic make-up
The territory of Rila Monastery Nature Park is made up mostly of metamorphic
complexes: gneisses, biotite-gneisses, amphibole-schists, amphibolites, mica schists,
and marbles, bordering to the north and south on large-grained granites, gneissgranites,
or are interspersed with fine-grained granites and pegmatite veins. The entire
bedrock is highly dislocated; therefore exogenetic processes have shaped up a rich
variety of forms. The metamorphic mantle of the Rila pluton follows a general incline
of 35 to 60 0 to the southwest. Transverse warping and faulting in a north-south and
east-west direction have caused the sinking of the tectonic layers towards the Rilska
River Valley, as evidenced particularly by the movement of the powerful largegrained
marble layer which, starting from the ridge of Yossifovitsa Peak (2,697 m)
and from Mermera Ridge (2,602 m) descends steadily to the west and crops out in the
Rilska River Valley at Otchov Dol (1,600m asl). As a reflection of the block-and-fault
structure of the Rila massif and under the influence of neotectonic movements, there
are several powerful ridges and imposing monoclinal crests. The most important
processes in the geological development of Rila Mountain by ages and periods are
presented in Appendix 8.
The rocks of the so-called gneiss-biotite and amphibolite suite are distinguished as a
strip of varying width stretching from Sapareva Banya to the River Bistritsa-Golyam
Mechi Peak, part of which falls within the park perimeter. The rocks are highly
fragmented, bent into isoclinal folds, assimilated, and in their southern end, reoriented
at the their point of contact with the granitoids of the batholite and the Kalin pluton.
Rila Monastery Nature Park
Management Plan -Draft
2004 - 2013
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