Cwm Idwal is a

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

(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 w ...

range of mountains in northern

Snowdonia Snowdonia, or Eryri (), is a mountainous region and National parks of the United Kingdom, national park in North Wales. It contains all 15 mountains in Wales Welsh 3000s, over 3000 feet high, including the country's highest, Snowdon (), which i ...

, the national park in the mountainous region of

North Wales North Wales ( ) is a Regions of Wales, 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 Snowdon ...

. Its main interest is to hill walkers and rock climbers, 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 (), alternatively relief or topographical relief, is the dimension and shape of a given surface of land. In physical geography, terrain is the lay of the land. This is usually expressed in terms of the elevation, slope, and orientati ...

(mountainous and rocky). In a 2005

poll Poll, polled, or polling may refer to: Forms of voting and counting * Poll, a formal election ** Election verification exit poll, a survey taken to verify election counts ** Polling, voting to make decisions or determine opinions ** Polling pla ...

conducted by ''

Radio Times ''Radio Times'' 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 September 1923 by John Reith, then general manage ...

'', 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 be ...

, 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. The term ''scree'' is ap ...

moraine A moraine is any accumulation of unconsolidated debris (regolith and Rock (geology), 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 gla ...

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

volcanic A volcano is commonly defined as a vent or fissure 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 fo ...

and

sedimentary rock Sedimentary rocks are types of rock (geology), rock formed by the cementation (geology), cementation of sediments—i.e. particles made of minerals (geological detritus) or organic matter (biological detritus)—that have been accumulated or de ...

which was laid down in a shallow

Ordovician The Ordovician ( ) is a geologic period and System (geology), system, the second of six periods of the Paleozoic Era (geology), Era, and the second of twelve periods of the Phanerozoic Eon (geology), Eon. The Ordovician spans 41.6 million years f ...

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 (geology), rock or sediment characterized by certain Lithology, lithologic properties or attributes that distinguish it from adjacent layers from which it is separated by v ...

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 glacier (; or ) is a persistent body of dense ice, a form of rock, that is constantly moving downhill under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires ...

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 and some alpine

saxifrage ''Saxifraga'' is the largest genus in the family Saxifragaceae, containing about 473 species of holarctic perennial plants, known as saxifrages or rockfoils. The Latin word ''saxifraga'' means literally "stone-breaker", from Latin ' ("rock" or " ...

s, such as tufted saxifrage (''Saxifraga cespitosa'') and '' Micranthes nivalis'', can be found. It is also a home of the Snowdon lily, a plant which can only be found in the UK on

Snowdon Snowdon (), or (), is a mountain in Snowdonia in North Wales. It has an elevation of above sea level, which makes it both the highest mountain in Wales and the highest in the British Isles south of the Scottish Highlands. Snowdon i ...

and its surroundings. Evan Roberts, the renowned botanist and explorer from Capel Curig, 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 Ice climbing is a climbing discipline that involves ascending routes consisting entirely of frozen water. To ascend, the ice climber uses specialist equipment, particularly double ice axes (or the more modern ice tools) and rigid crampons. ...

during the winter. The Cwm is also popular for

hill walking Walking is one of the most popular outdoor recreational activities in the United Kingdom, and within England and Wales there is a comprehensive network of rights of way that permits access to the countryside. Furthermore, access to much uncultiva ...

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 can be described as being between hiking and climbing, rock climbing. "A scramble" is a relat ...

, given its proximity to

Tryfan Tryfan () is a mountain in the Ogwen Valley, Snowdonia, Wales. It forms part of the Glyderau group, and is one of the most recognisable peaks in Britain, having a classic pointed shape with rugged crags. At above sea level, it is the fifteent ...

and Glyder Fach and

Glyder Fawr Glyder Fawr is a mountain in Snowdonia, Wales, the highest peak in the Glyderau range at just over 1,000 metres. It is the fifth-highest mountain in Wales and has several walking and scrambling routes leading to its summit. According to Sir I ...

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 (), known locally as Sagarmatha in Nepal and Qomolangma in Tibet, is Earth's highest mountain above sea level. It lies in the Mahalangur Himal sub-range of the Himalayas and marks part of the China–Nepal border at it ...

and

Kangchenjunga Kangchenjunga 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 Tamur River, in the north by the Lhonak River and Jongsang La, and ...

, held at

Pen-y-Gwryd Pen-y-Gwryd is a mountain pass, pass at the head of Nantygwryd and Nant Cynnyd rivers close to the foot of Snowdon in Gwynedd, Wales. The area is located at the junction of the A4086 road, A4086 from Capel Curig to Llanberis and Caernarfon and t ...

, many of whom were keen

geologist A geologist is a scientist who studies the structure, composition, and History of Earth, history of Earth. Geologists incorporate techniques from physics, chemistry, biology, mathematics, and geography to perform research in the Field research, ...

s and

botanist Botany, also called plant science, is the branch of natural science and biology studying plants, especially Plant anatomy, their anatomy, Plant taxonomy, taxonomy, and Plant ecology, ecology. A botanist or plant scientist is a scientist who s ...

References

External links

* Cwm Idwal 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