Mrazové srázy u Lazen

Mrazové srázy u Lazen ("Frost Escarpments near Lazny") is a small but geologically remarkable nature reserve in the Šumava mountains, tucked away on the south-eastern edge of the hamlet of Lazny in the Klatovy district. The protected area sits on the north-north-western slope of the hill U Valcháře (711 m), at elevations between 625 and 670 meters, and covers just 1.86 hectares. Despite its modest size, the site has drawn the attention of geomorphologists for nearly a century.

What are "frost escarpments"?

The reserve's name refers to a distinctive landform created by frost weathering — the process by which water freezing inside rock cracks gradually splits the stone apart. The result here is a well-developed block field (a stony scree slope) together with frost escarpments, steep rocky faces shaped by repeated freezing and thawing of water within fissures. It is a textbook example of periglacial processes that shaped the Šumava landscape during colder climatic periods.

Why was it protected?

The story of the site's protection goes back to the 1930s, when its geomorphological value was first recognized by Josef Kunský, a geomorphologist born in nearby Sušice and one of the pioneers of landform research in this part of the Czech lands. Formal protected status, however, came much later: the reserve was established by a resolution of the council of the former District National Committee in Klatovy on 8 April 1976. The reason for protection was precisely this well-preserved block field together with its accompanying frost escarpments — a landform typical of the Šumava's geological development, yet rarely found in such a clearly readable form.

Landscape and surroundings

The reserve lies within the Šumavské pláně (Šumava Plains), one of the gentler, more rolling sections of the wider Šumava range, south of the village of Strašín. The surrounding countryside is a typical mosaic of forests and meadows, and the slope with its rocky rubble stands in clear contrast to the softer terrain nearby. The block field is partly covered with mosses and lichens, which only underlines its raw, geological character.

Who is it for?

Mrazové srázy u Lazen is above all a destination for visitors interested in geology and geomorphology. The reserve is small and has no developed tourist infrastructure, but it offers a near-textbook example of a natural process rarely seen so clearly in the field. It also makes a worthwhile stop for hikers exploring the area around Strašín and the wider Šumava who want to add something more than scenery to their route.

Frequently asked questions

What exactly are "frost escarpments"? They are steep rock faces together with an accompanying block field (stony scree), formed by the repeated freezing and thawing of water in rock fissures — a classic frost-weathering process typical of mountain areas with a colder climate.

When was the reserve established? The site's value was first recognized in the 1930s thanks to geomorphologist Josef Kunský, but it only received formal protected status through a resolution dated 8 April 1976.

How large is the protected area? The reserve covers 1.86 hectares, at elevations between 625 and 670 meters above sea level.

Where exactly is it located? On the south-eastern edge of the hamlet of Lazny, on the slope of the U Valcháře hill (711 m), in the Klatovy district, within the Šumava mountains.