Walking in Bulgaria's National Parks. Julian Perry

      Cascade along the trail to hizha Dobrila (Walk 2, Day 2)

      Climate

      Not surprisingly, on account of its west–east alignment across the length of Bulgaria, the Stara Planina forms a significant climatic barrier whose influence is felt throughout the country. The northern slopes of the range experience a moderate-continental climate, while the southern slopes experience a transitional-continental climate with some Mediterranean influences. Within the Central Balkan national park itself, factors such as altitude and slope exposition also have a profound influence on the local micro-climate.

      The average annual temperature within the national park is 7°C, but this figure is lower at higher altitudes, dropping to between zero and 2°C at altitudes above 2000m. Summer temperatures are often surprisingly warm, with a July average varying between 16°C and 22°C at lower altitudes, and between 7°C and 17°C at altitudes over 1000m. Winters, by contrast, tend to be very cold, with average January temperatures of between -1°C to -3°C at lower altitudes and between -3°C and -9°C above 1000m.

      For walkers, one of the most important climatic characteristics that must be taken into account when venturing into the Central Balkan national park is fog. The Stara Planina as a whole is notorious for this, with the region of the national park experiencing on average some 270 days per year with foggy conditions. This figure rises to a staggering 305 days on the highest peak Botev. May and June tend to be worst in this respect, and the winter months of January and February are also fairly bad. For those in search of the sunniest and clearest weather, then August is usually the best bet.

      At lower altitudes, the average annual precipitation within the Central Balkan national park varies from 550mm to 1000mm, with the southern slopes being notably drier than those to the north. At altitudes above 1000m, the average annual precipitation reaches 1200mm, and at hizha Ambaritsa on the northern flank of the range it is 1360mm, making this one of the wettest places in Bulgaria. Maximum precipitation occurs in early summer (typically during June) and is lowest in winter (usually in February).

      During winter, precipitation tends to fall as snow. The first fleeting flurries can often be seen in September or October, but it is not usually until November that any dusting of snow is likely to remain permanent. The snow cover then gradually accumulates over the ensuing months, in March reaching a maximum depth of between 150cm and 220cm at altitudes above 2000m. At higher altitudes, the snow cover tends to last between 150 to 180 days, while in lower parts of the national park the duration is typically 75 to 80 days. Avalanches are a serious menace in the region during the winter months, typically in the high mountain treeless zone between 1500m and 2200m.

      Another feature of the climate in the Stara Planina is the wind. The summit of Murgash (1687m) in the Western Stara Planina has the highest average annual wind speed in the country, with Botev (2376m) in the Central Balkan national park coming in a close second. In general, the average annual wind speed on the main ridge typically tops 10m/s, but it is not unusual for even stronger winds to be experienced in the region. One such wind is the föhn, a warm dry spring wind that whips up from the south and then gusts over the ridge, at times reaching speeds of between 18m/s and 20m/s. There is also a biting northerly wind, know as the bora, which blasts across the ridge and sweeps down over the southern slopes. Typical winds, however, tend to be northwesterly and of moderate strength.

      Up-to-date weather information and forecasts for the Central Balkan region can be found at http://vremeto.v.bg, and then follow the link for Peak Botev.

      Plant Life

      The flora of the Central Balkan national park is extremely rich and varied, with approximately 1900 species and sub-species of higher plants found growing in the region. These include 67 Balkan endemics, 10 Bulgarian endemics, and 10 local endemics that are unique to this part of the Stara Planina. The latter include three species of lady’s mantle Alchemilla achtarowii, Alchemilla jumrukczalica and Alchemilla asteroantha, as well as Ognyanov’s knapweed (Centaurea ognianoffi), Urumov’s hawkweed (Hieraceum urumoffii), Bulgarian seseli (Seseli bulgaricum), two catchflies Silene balcanica and Silene trojanensis, the mullein Verbascum boevae and the beautiful little primrose Primula frondosa.

      While walking through the Central Balkan national park you will pass through six distinct vegetation zones. Around the lowest edge of the national park, between about 550m and 900m, there are patches of oak forest. Typically these comprise Turkey oak (Quercus cerris), Hungarian oak (Quercus frainetto) or downy oak (Quercus pubescens), and also include secondary associations of eastern hornbeam (Carpinus orientalis), prickly juniper (Juniperus oxycedrus), hop-hornbeam (Ostrya carpinifolia), manna ash (Fraxinus ornus) and Tartar maple (Acer tartaricum). Many of the trees in this zone are stunted by decades of cutting and grazing, and resemble thickets rather than mature woodland.