Cwm Idwal is a

cirque A (; from the Latin word ') is an amphitheatre-like valley formed by glacial erosion. Alternative names for this landform are corrie (from Scottish Gaelic , meaning a pot or cauldron) and (; ). A cirque may also be a similarly shaped landf ...

(or corrie) in the

Glyderau The Glyderau (a Welsh plural form, also known in English as the Glyders) are a mountain group in Snowdonia, North Wales. The name derives from the highest peaks in the range, Glyder Fawr and Glyder Fach. According to Sir Ifor Williams, the word ...

range of mountains in northern

Snowdonia Snowdonia or Eryri (), is a mountainous region in northwestern Wales and a national park of in area. It was the first to be designated of the three national parks in Wales, in 1951. Name and extent It was a commonly held belief that the na ...

, the national park in the mountainous region of

North Wales North Wales ( cy, Gogledd Cymru) is a region of Wales, encompassing its northernmost areas. It borders Mid Wales to the south, England to the east, and the Irish Sea to the north and west. The area is highly mountainous and rural, with Snowdonia N ...

. Its main interest is to hill walkers and

rock climbers Rock climbing is a sport in which participants climb up, across, or down natural rock formations. The goal is to reach the summit of a formation or the endpoint of a usually pre-defined route without falling. Rock climbing is a physically an ...

, but it is also of interest to geologists and naturalists, given its combination of altitude (relatively high in UK terms), aspect (north-facing) and

terrain Terrain or relief (also topographical relief) involves the vertical and horizontal dimensions of land surface. The term bathymetry is used to describe underwater relief, while hypsometry studies terrain relative to sea level. The Latin w ...

(mountainous and rocky). In a 2005 poll conducted by

Radio Times ''Radio Times'' (currently styled as ''RadioTimes'') is a British weekly listings magazine devoted to television and radio programme schedules, with other features such as interviews, film reviews and lifestyle items. Founded in May 1923 by J ...

, Cwm Idwal was ranked the 7th greatest natural wonder in Britain.

Geology

Cwm Idwal is a spectacular product of

glaciation A glacial period (alternatively glacial or glaciation) is an interval of time (thousands of years) within an ice age that is marked by colder temperatures and glacier advances. Interglacials, on the other hand, are periods of warmer climate bet ...

, surrounded by high crags,

scree Scree is a collection of broken rock fragments at the base of a cliff or other steep rocky mass that has accumulated through periodic rockfall. Landforms associated with these materials are often called talus deposits. Talus deposits typically ha ...

moraine A moraine is any accumulation of unconsolidated debris ( regolith and rock), sometimes referred to as glacial till, that occurs in both currently and formerly glaciated regions, and that has been previously carried along by a glacier or ice sh ...

s and rounded rocks, with a lake on its floor ( Llyn Idwal). Cwm Idwal comprises

volcanic A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often found where tectonic plates ...

and

sedimentary rock Sedimentary rocks are types of rock that are formed by the accumulation or deposition of mineral or organic particles at Earth's surface, followed by cementation. Sedimentation is the collective name for processes that cause these particle ...

which was laid down in a shallow

Ordovician The Ordovician ( ) is a geologic period and system, the second of six periods of the Paleozoic Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period million years ago (Mya) to the start of the Silurian Period Mya. ...

sea, and later folded to give rise to the distinctive trough-shaped arrangement of

strata In geology and related fields, a stratum ( : strata) is a layer of rock or sediment characterized by certain lithologic properties or attributes that distinguish it from adjacent layers from which it is separated by visible surfaces known as e ...

known today as the Idwal

Syncline In structural geology, a syncline is a fold with younger layers closer to the center of the structure, whereas an anticline is the inverse of a syncline. A synclinorium (plural synclinoriums or synclinoria) is a large syncline with superimposed ...

. This fold in the rock is visible today, thanks to the layering of the sedimentary rocks. The area was then eroded by

glacial A glacial period (alternatively glacial or glaciation) is an interval of time (thousands of years) within an ice age that is marked by colder temperatures and glacier advances. Interglacials, on the other hand, are periods of warmer climate betwe ...

action to form the classic semicircular valley.

Botany

Given its elevation and north-facing aspect, Cwm Idwal is the most southerly place in Britain where Arctic plants such as

moss campion ''Silene acaulis'', known as moss campion or cushion pink, is a small mountain-dwelling wildflower that is common all over the high arctic and tundra and in high mountains of Eurasia and North America (Alps, Carpathians, southern Siberia, Pyrene ...

and some alpine saxifrages, such as tufted saxifrage (''Saxifraga cespitosa'') and '' Micranthes nivalis'', can be found. It is also a home of the

Snowdon lily ''Gagea serotina'', synonym ''Lloydia serotina'', is an Arctic–alpine flowering plant of the lily family. It is widespread across the mountainous parts of western North America, from Alaska to New Mexico, and in Europe is found in the Alps an ...

, a plant which can only be found in the UK on

Snowdon Snowdon () or (), is the highest mountain in Wales, at an elevation of above sea level, and the highest point in the British Isles outside the Scottish Highlands. It is located in Snowdonia National Park (') in Gwynedd (historic ...

and its surroundings. Evan Roberts, the renowned botanist and explorer from

Capel Curig Capel Curig (; meaning "Curig's Chapel") is a village and community in Conwy County Borough, Wales. Historically in Caernarfonshire, it lies in the heart of Snowdonia, on the River Llugwy, and has a population of 226, reducing slightly to 206 ...

, did probably as much as any other (self-taught) botanist to document the area. The Snowdonia hawkweed, '' Hieracium snowdoniense'' is only known to occur in Cwm Idwal.

Rock climbing

Rhiwiau Caws (Idwal Slabs) and the cliffs around the head of Cwm Idwal are a popular area for rock climbing; Rhiwiau Caws (on the eastern side of the Cwm) in particular are popular with inexperienced climbers learning their skills. They were first climbed in 1897 by Rose and Moss. Twll Du has some excellent ice climbing during the winter. The Cwm is also popular for hill walking and

scrambling Scrambling is a mountaineering term for ascending steep terrain using one's hands to assist in holds and balance.''New Oxford American Dictionary''. It is also used to describe terrain that falls between hiking and rock climbing (as a “scram ...

, given its proximity to Tryfan and Glyder Fach and

Glyder Fawr is a mountain in Snowdonia, Wales, the highest peak in the Glyderau range at just over 1,000 metres, having had its height recalculated in 2010 using GPS. It is the fifth-highest mountain in Wales and has several walking and scrambling route ...

and their profusion of rocky ridges. In the mid-to-late 1950s and into the 1960s, this was the reunion excursion campsite of the first ascenders of

Mount Everest Mount Everest (; Tibetan: ''Chomolungma'' ; ) is Earth's highest mountain above sea level, located in the Mahalangur Himal sub-range of the Himalayas. The China–Nepal border runs across its summit point. Its elevation (snow ...

and

Kangchenjunga Kangchenjunga, also spelled Kanchenjunga, Kanchanjanghā (), and Khangchendzonga, is the third highest mountain in the world. Its summit lies at in a section of the Himalayas, the ''Kangchenjunga Himal'', which is bounded in the west by the ...

, held at Pen-y-Gwryd, many of whom were keen

geologist A geologist is a scientist who studies the solid, liquid, and gaseous matter that constitutes Earth and other terrestrial planets, as well as the processes that shape them. Geologists usually study geology, earth science, or geophysics, alt ...

s and botanists. LlynIdwal-p01

References

External links

* is at coordinates / {{gbmappingsmall, SH 641 593 Llandygai Capel Curig Tourism in Conwy County Borough Tourism in Gwynedd Tourism in Snowdonia Valleys of Conwy County Borough Valleys of Gwynedd Valleys of Snowdonia Climbing areas of Wales National nature reserves in Wales