The Glyderau (a
Welsh plural form, also known in English as the Glyders) are a
mountain
A mountain is an elevated portion of the Earth's crust, generally with steep sides that show significant exposed bedrock. Although definitions vary, a mountain may differ from a plateau in having a limited summit area, and is usually higher t ...
group in
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 ...
, North
Wales
Wales ( ) is a Countries of the United Kingdom, country that is part of the United Kingdom. It is bordered by the Irish Sea to the north and west, England to the England–Wales border, east, the Bristol Channel to the south, and the Celtic ...
. The name derives from the highest peaks in the range,
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
Glyder Fach. According to Sir
Ifor Williams, the word "Glyder" derives from the
Welsh word "Cludair", meaning a heap of stones.
The Glyderau stretch from
Mynydd Llandegai to
Capel Curig, and include five of Wales' fourteen or fifteen
summits over 3000 feet; these include
Tryfan, considered one of the finest mountains in Wales and one of the few mountains on the
British mainland requiring
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 ...
to reach the summit. The eastern half of the range in particular, including Glyder Fawr, Glyder Fach and Tryfan, is very popular with walkers and climbers.
Dinorwig Power Station, a
hydroelectric
Hydroelectricity, or hydroelectric power, is Electricity generation, electricity generated from hydropower (water power). Hydropower supplies 15% of the world's electricity, almost 4,210 TWh in 2023, which is more than all other Renewable energ ...
pump-storage system, is located in a man-made cavern within
Elidir Fawr. The slopes of the Glyderau also include the lake
Llyn Idwal, and a number of classic
climbing
Climbing is the activity of using one's hands, feet, or other parts of the body to ascend a steep topographical object that can range from the world's tallest mountains (e.g. the eight thousanders) to small boulders. Climbing is done for locom ...
areas such as Rhiwiau Caws.
Geography
The Glyderau were formed in the
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 ...
period about 500 million years ago as the result of two land masses moving together and causing the Snowdonia massif to rise up. Since then, erosion and the advance and retreat of
glacier
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 ...
s during the Ice Ages has worn down the mountains to their present proportions. The underlying rock is a mixture of sedimentary and volcanic material. The last ice sheet retreated about 10,000 years ago and
Cwm Idwal is a good example of a cirque formed by the ice. The main glacier flowed down the adjoining
Nant Ffrancon Valley, a route now followed by the A5 road, and Cwm Idwal housed a side glacier. The ice scarred the surrounding cliffs, hollowed out the bed of
Llyn Idwal and dumped rocks and other material that formed
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 at its foot. Massive boulders and shattered rocks crashed down from above to form the boulder fields and
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 ...
s.
[
The land was originally covered with native forest mostly consisting of ]birch
A birch is a thin-leaved deciduous hardwood tree of the genus ''Betula'' (), in the family Betulaceae, which also includes alders, hazels, and hornbeams. It is closely related to the beech- oak family Fagaceae. The genus ''Betula'' contains 3 ...
and oak
An oak is a hardwood tree or shrub in the genus ''Quercus'' of the beech family. They have spirally arranged leaves, often with lobed edges, and a nut called an acorn, borne within a cup. The genus is widely distributed in the Northern Hemisp ...
. This was cleared over the millennia by the Neolithic, Bronze Age and Iron Age farmers that settled here and now there is little tree cover. Groups of feral
A feral (; ) animal or plant is one that lives in the wild but is descended from domesticated individuals. As with an introduced species, the introduction of feral animals or plants to non-native regions may disrupt ecosystems and has, in som ...
goat
The goat or domestic goat (''Capra hircus'') is a species of Caprinae, goat-antelope that is mostly kept as livestock. It was domesticated from the wild goat (''C. aegagrus'') of Southwest Asia and Eastern Europe. The goat is a member of the ...
s can still be found on the Glyderau, probably the remnants of the herds that were farmed here a thousand years ago. The large number of sheep that now graze the common land were introduced in the 18th century with the rise of the woollen industry.[
]
Access
The Glyderau present a much more rocky appearance than the smooth rounded humps of the Carneddau just to the north. The ridge between the summits of Glyder Fawr and Glyder Fach is covered with coarse grasses and heathers and strewn with boulders and slabs of rocks. The ascent to the summit of Tryfan requires scrambling rather than just walking. Tryfan, Glyder Fach and the cliffs around Cwm Idwal offer rock climbing with routes ranging from those suitable for beginners to those requiring great technical expertise. The mountains can be approached from Llyn Ogwen to the north, where there is a car park, or from Nant Peris
The Llanberis Pass (; alternative English name, Pass of Llanberis) in Snowdonia carries the main road (A4086) from the south-east to Llanberis, over Pen-y-Pass, between the mountain ranges of the Glyderau and the Snowdon massif. At the bottom o ...
in the Llanberis Pass where there is a park and ride service. Buses run hourly from Bangor to Llanberis and there is a less frequent service from Bethesda to Llyn Ogwen.
Cwm Idwal
The north-facing amphitheatre
An amphitheatre (American English, U.S. English: amphitheater) is an open-air venue used for entertainment, performances, and sports. The term derives from the ancient Greek ('), from ('), meaning "on both sides" or "around" and ('), meani ...
-shaped valley of Cwm Idwal with its dark cliffs has a unique flora
Flora (: floras or florae) is all the plant life present in a particular region or time, generally the naturally occurring (indigenous (ecology), indigenous) native plant, native plants. The corresponding term for animals is ''fauna'', and for f ...
, and some plants here are the most southerly remnants in Britain of the Arctic/Alpine flora. The Snowdon lily (''Lloydia serotina'') is found here, high on mountain ledges, the only place in Britain where it is found. Other Alpine species include the purple saxifrage (''Saxifraga oppositifolia''), tufted saxifrage (''Saxifraga cespitosa''), Alpine meadow rue (''Thalictrum alpinum'') and mountain sorrel
''Oxyria digyna'' (mountain sorrel, wood sorrel, Alpine sorrel or Alpine mountain-sorrel) is a species of flowering plant in the buckwheat family (Polygonaceae).Sierra Nevada Wildflowers, Karen Wiese, 2nd ed., 2013, p. 108 It is native to arctic ...
(''Oxyria digyna''). Because of the scientific interest of this valley, sheep have been excluded from it to allow the native plants to flourish and it has been made into a national nature reserve. The lake itself is shallow and fringed with rushes, reeds and bottle sedge (''Carex rostrata''). Plants growing in the water or on the damp ground nearby include awlwort, pillwort, waterwort and spring quillwort (''Isoetes echinospora''). Other plants growing on damp shady ledges include the Welsh poppy (''Meconopsis cambrica''), the wood-rush (''Lazula sylvatica''), water avens (''Geum rivale''), wood anemone (''Anemone nemorosa'') and goldenrod
Goldenrod is a common name for many species of flowering plants in the sunflower family, Asteraceae, commonly in reference to the genus ''Solidago''.
Several genera, such as ''Euthamia'', were formerly included in a broader concept of the genu ...
(''Solidago virgaurea''). Animals that live here include badger
Badgers are medium-sized short-legged omnivores in the superfamily Musteloidea. Badgers are a polyphyletic rather than a natural taxonomic grouping, being united by their squat bodies and adaptions for fossorial activity rather than by the ...
s, foxes and polecats as well as buzzards (''Buteo buteo''), peregrine falcon
The peregrine falcon (''Falco peregrinus''), also known simply as the peregrine, is a Cosmopolitan distribution, cosmopolitan bird of prey (raptor) in the family (biology), family Falconidae renowned for its speed. A large, Corvus (genus), cro ...
s (''Falco peregrinus''), choughs (''Pyrrhocorax pyrrhocorax''), skylarks (''Alauda arvensis''), black grouse (''Tetrao tetrix'') and red grouse
The red grouse (''Lagopus scotica'') is a medium-sized bird of the grouse family which is found in Calluna, heather moorland in Great Britain and Ireland.
It was formerly classified as a subspecies of the willow ptarmigan (''Lagopus lagopus'') ...
(''Lagopus lagopus'').[
In the cliffs above Llyn Idwal is a dark cleft in the rock known as Twll Du from which plumes of mist sometimes emanate. These were believed to be caused by ancient ]druid
A druid was a member of the high-ranking priestly class in ancient Celtic cultures. The druids were religious leaders as well as legal authorities, adjudicators, lorekeepers, medical professionals and political advisors. Druids left no wr ...
s creating lightning bolts to keep the invading Romans at bay. Llyn Idwal itself was said to be named after a drowned boy, either the son of 8th century Prince Cadwalader, murdered by a rival, or the son of 12th century Prince Owain Gwynedd
Owain ap Gruffudd ( – 23 or 28 November 1170) was King of Gwynedd, North Wales, from 1137 until his death in 1170, succeeding his father Gruffudd ap Cynan. He was called Owain the Great () and the first to be styled "Prince of Wales" and th ...
and killed by his uncle. The traveler Thomas Pennant
Thomas Pennant (16 December 1798) was a Welsh natural history, naturalist, traveller, writer and antiquarian. He was born and lived his whole life at his family estate, Downing Hall, near Whitford, Flintshire, in Wales.
As a naturalist he had ...
, writing in the 1780s, stated that the local shepherds were in awe of the lake believing it to be "the haunt of Demons, and that no bird dare fly over its damned waters".[
]
Dinorwig Power Station
Deep inside the mountain of Elidir Fawr there is a power station and many miles of tunnels. Dinorwig Power Station, a pumped storage hydroelectric
Hydroelectricity, or hydroelectric power, is Electricity generation, electricity generated from hydropower (water power). Hydropower supplies 15% of the world's electricity, almost 4,210 TWh in 2023, which is more than all other Renewable energ ...
facility, was originally built to provide back up facilities and water storage to smooth out the peaks and troughs in demand associated with the inflexible output of nuclear power stations. When demand is low, water is pumped up the mountain and stored in Marchlyn Mawr reservoir, previously a slate
Slate is a fine-grained, foliated, homogeneous, metamorphic rock derived from an original shale-type sedimentary rock composed of clay or volcanic ash through low-grade, regional metamorphism. It is the finest-grained foliated metamorphic ro ...
quarry. The water is released to flow through turbine
A turbine ( or ) (from the Greek , ''tyrbē'', or Latin ''turbo'', meaning vortex) is a rotary mechanical device that extracts energy from a fluid flow and converts it into useful work. The work produced can be used for generating electrical ...
s during times of high demand for electricity. The power is conveyed through underground cables to join the grid so as to have little visual impact on the Snowdonia National Park skyline.
Management
The National Trust
The National Trust () is a heritage and nature conservation charity and membership organisation in England, Wales and Northern Ireland.
The Trust was founded in 1895 by Octavia Hill, Sir Robert Hunter and Hardwicke Rawnsley to "promote the ...
took over the management of the Glyderau and the Carneddau
The (lit. 'the cairns'; is a Welsh language, Welsh plural form, and is sometimes anglicised to ''Carnedds'') are a group of mountains in Snowdonia, Wales. They include the largest contiguous areas of high ground (over or high) in England and W ...
in 1951 in lieu of death duties on the Penrhyn Estate. The total area is about 7,000 hectares, half of which is common land
Common land is collective land (sometimes only open to those whose nation governs the land) in which all persons have certain common rights, such as to allow their livestock to graze upon it, to collect wood, or to cut turf for fuel.
A person ...
with registered grazing rights for 45,000 sheep and 741 ponies. There are eight tenanted farms on the estate and the National Trust is responsible for the maintenance of footpaths and drystone walls, some of which date back many hundreds of years. The two mountain ranges form part of the Snowdonia National Park
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 ...
.
Mountains in the Glyderau
This is a list of the main summits in the range, in order from west to east.
* Elidir Fawr (924 m)
* Carnedd y Filiast (821 m)
* Mynydd Perfedd (813 m)
* Foel Goch (831 m)
* Y Garn (947 m)
* 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 ...
(1,001 m)
* Glyder Fach (994 m)
* Tryfan (918 m)
* Y Foel Goch (805 m)
* Gallt yr Ogof (763 m)
* Cefn y Capel (c.460 m )
In popular culture
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 ...
are mentioned in, and form part of the setting for, the Half Man Half Biscuit
Half Man Half Biscuit are an English rock band, formed in 1984 in Birkenhead, Merseyside. Known for their satirical, sardonic, and sometimes surreal songs, the band comprises lead singer and guitarist Nigel Blackwell, bassist and singer Neil Cr ...
song "Evening Of Swing (Has Been Cancelled)".
References
External links
Walks in the Glyderau
{{Welsh3000
Capel Curig
Llanberis
Llanddeiniolen
Llandygai
Mountains and hills of Conwy County Borough
Mountains and hills of Gwynedd
Mountains and hills of Snowdonia