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Po vrcholech CHKO České středohoří

Borec Hill – ventarol system

Volcanic Borec Hill is penetrated by many rifts created by volume changes which accompanied final crystallization of burning magma and rock expansion. These rifts came to surface due to erosion and can be found on the foothill and the peak. The presence of micro-exhalations – so called ventarols, tiny outflows of warm and moist air to the surface can be seen especially in winter. Warm moist air rises up while the vents on the foothill draw cold air in. During summer the heavier 4°C cold air “leaks” thru the holes on the foothill (similar effect occurs also on a nearby Sutom Hill). The differences in temperature inside those ventarols (measured already in 1881) are negatively correlated to outside temperature, because the temperature in the ventarols doesn´t diminish under 9 – 10°C, thus the biggest temperature difference can be measured in January and February (as much as 16 to 20°C difference). During sunny winter days, the humidity in these cracks as much as doubles. These ventarols can be easily seen in the snow as dark spots, or small lace-like frosts, or stalactites on surrounding bushes and trees. On the other side, one can see snow pits on Plesivec Hill, where the icy snow lasts till summer. Such quantity of ventarols cannot be found anywhere else in Ceske stredohori (Czech Central Mountains). The ventarol system was recorded on Borec in 1833, but mistaken for volcanic exhalations. Ventarols were named from Latin “velus” (wind) and because of them Borec Hill is visited year round.

Ventaroly

Ventaroly

Ventaroly

Ventaroly

řez

řez

GPS position

N 50° 30.850', E 13° 59.326'
[GPX]

[MAPY.CZ]

Contact

Památky jinak, o.s.
Věra Gruntorádová
Tel.:774114586
e-mail:pamatkyjinak@gmail.com
http://www.pamatky-jinak.webnode.cz