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Deiniolen to Ogwen via Glyderau and Y Gribin Ridge Scramble

By Dave Roberts   

on September 3, 2014    No ratings yet.

Deiniolen to Ogwen via Glyderau and Y Gribin Ridge Scramble

Further Details

Route Summary:

A traverse of the Glyderau, including a tricky descent of the Gribin ridge.

This walk includes the 4 Washis of Glyder Fawr, Y Garn (Glyderau), Elidir Fawr, Foel-goch

This walk includes the 4 Hewitts of Glyder Fawr, Y Garn (Glyderau), Elidir Fawr, Foel-goch

This walk includes the 4 Nuttalls of Glyder Fawr, Y Garn (Glyderau), Elidir Fawr, Foel-goch

Route Start Location: Deiniolen / Dinorwig to Ogwen

13.32 km 1037 m 7 hours

Calculate the time using Naismith’s Rule and factor in your own pace.

Activivity Type: Hard Walk, Scrambling, Scrambling Grade 1

Summits and Places on this Route


Shop in Deinolen, snack kiosk and toilets and seasonal cafe in Ogwen.


Steep scree up Glyder Fawr, Route finding in mist. Down Scramble of Y Gribin Ridge has a couple of steep sections – read our Glyder Fach via Y Gribin for more information on this scramble.

Remember that we cannot outline every single hazard on a walk – it’s up to you to be safe and competent. Read up on Mountain Safety , Navigation and what equipment you’ll need.

Parking :

Public Transport:

Sherpa Buses and local buses from Caernarfon and Bangor.

Traveline for UK Public Transport

Recommended Maps


Deiniolen to Ogwen via Glyderau and Y Gribin Ridge Scramble Ordnance Survey Map and GPX File Download

Download file for GPS

Deiniolen to Ogwen via Glyderau and Y Gribin Ridge Scramble

This is an excellent way to bag most of the Glyderau in one trip by ascending Elidir from Deiniolen and finally descending via the scrambly Gribin to Ogwen. This trip provides a different approach to the walk, but does leave the typical car-dependent walker stuck. Creative use of public transport and taxis are the best way.You could alternatively start in Ogwen and ascend Carnedd y Filiast, and then return via this route.

Deiniolen to Ogwen via Glyderau and Y Gribin Ridge Scramble Route Description

The walk starts from the Crossroads on the access road to Marchllyn Mawr reservoir at SH593 631. If you start from bus stops in Deinolen or Dinorwig, then you only add a kilometre or so to the trip. Follow the access road uphill, through some gates and you can now follow the road as opposed to having to walk alongside it on a very rough path.


Soon after passing a quarry to your right, a track veers off right and immediately forks left and right. The left fork leads to Marchllyn Bach, and has a locked gate. Climb over the gate and follow the fence right. A faint path can be seen, that soon splits as you go uphill into routes of varying steepness. You need to be aiming for the skyline, preferably veering to your right as the minor summit of Elidir Fach is the day’s first goal. The grassy slope is a little tedious, but once views open up towards Llyn Padarn and Marchllyn Mawr, it becomes much more pleasant. Neither is it a long slog like it’s counterpart from Nant Peris, and you reach the skyline and the long broad summit spur of Elidir Fach.


From Elidir Fach, the views are extensive. You’re on the edge of the park, yet quite high as well. Snowdon and Crib goch to one side, across Nantlle, Ynys Mon and on to the Carneddau. Plus the scree covered lump of Elidir Fawr behind you. If it’s clear, you can make out the path that crosses the scree at an angle away from you. If it’s misty, then there’s a fence that can be followed to the summit ridge. Even if it’s clear, the closer yo get to the path, the more difficult it is to spot. Once on it, then it’s abundantly clear.


Twenty minutes should see you clear the scree and a few more to clamber over the rocks to the summit shelter that’s well sunk in and actually provides shelter. If the views from Elidir Fach were good, then they just got better. The good thing about this walk is that the views will keep on changing all day, and are all equally spectacular. I finally confirmed that I could see the Lakes, and probably what were the Wicklow Mountains, Isle Of Man and a feature in between that I could see all day that were in all likelyhoods the Mountains of Mourne in Northern Ireland!


Continue over the summit and follow the path northwards. It contours the top of Cwm Dudodyn, and the base of Mynydd Perfedd that you really may as well ascend too. You quickly arrive at the base of Y Foel Goch, the ascent ahead being clearly apparent. The slog up scree isn’t as bad as it first looks, and you find yourself almost on top before you start getting fed up with it. It steepens as you near the top, but then abruptly flattens off into a large grassy plateau. The summit itself is a small area with sheer drops on most sides, so take care in mist. Follow the fence that crosses the summit (right, obviously not left) and easy walking takes you over grass to the next ascent, Y Garn.


Yet another scree path takes you up this fine mountain. It’s a pleasant path, for scree. If you don’t think so, you will once you experience the scree path(s) up Glyder Fawr. Some snow remained near the summit today, apparently two weeks old. It was bitterly cold out of the sun, but pleasantly warm in it. Descending from the Garn towards Llyn y Cwn, I realised that the lake was frozen. Even the outlet river was partly frozen over. Looking at the lake is a great distraction from facing the great scree slopes of Glyder Fawr in one go. There are always people struggling on here when I arrive. Either you can hear their screams, or hear scree sliding down. Today a group was stuck for a while half way up, having taken what they thought was an easier route (it wasn’t!), but they soon got moving again as stopping on the steep scree is just as uncomfortable as walking. You’ll probably get overtaken on here by an eighty year old, and someone walking their dogs who have clearly found ways to walk uphill by defying gravity. “Steep this isn’t it?”, well it didn’t bloody well stop him from steaming up!


Finally, the angle eases and you can huff your way towards one of the large piles of rocks that could be the summit. The path veers left, and this takes you to the base of the summit rocks by avoiding the rougher boulders (you’ll thank me for that in the wet). It was pretty busy here for a February, and a Monday at that. It looked more like a summer’s day, especially as people are wandering about in shorts and some guys without shirts (bravado more than a practical need, for definite).


The path follows some cairns that are vital in mist, and take you across a sea of stones towards the Bwlch y Ddwy Glyder. Usually I’d continue, but today I decided to descend by Y Gribin. The top of which is marked by a shelter. Be warned. It is a scramble, not just a rocky walk as I’d been ed to believe in certain guides. Going up it wouldn’t be technically difficult, but descending it I seemed to find all the awkward parts. I could have done with my walking rope at a few steep sections where I ended up sliding down long, steep slabs by slowing my progress with whatever friction I could produce. There is a path, but it’s steep and a little unpleasant; I prefer my chances on solid rock. It didn’t help my cause that my left knee was again stiffening up after a brisk road walk on Saturday.


It’s only the upper section of the scramble that causes any sort of difficulty, with a decent path taking you down the rest of the way. The best thing about this is that you can relax a bit and take in the views that have improved yet again. You have Tryfan and Llyn Bochlwyd to one side, Garn and Devil’s Kitchen to the other and the sheer cliffs of the Glyderau behind you. It is a truly magnificent place, and that alone makes this descent worthwhile. Tryfan was mocking me, I’d planned to ascend it today but I couldn’t get to my starting point early enough. Next time I see sunshine, it’s top of the list.


Normally, on reaching the bottom of the ridge at Llyn Bochlwyd, you’re almost there. You can go left into Cwm Idwal down a steep path, or right and down past the river direct to Ogwen Cottage. I took the direct route, knowing it was easy steps all the way. What i didn’t know was that the steps were all solidly iced up and the descent was lethal instead of easy. Still, at least the snack kiosk at Ogwen was open, so it wasn’t all bad. A warm sausage roll and a couple of hot coffees from there saw me fully recovered again.

Dave Roberts founded Walk Eryri in 2004, with the aim of providing routes that are off the beaten track. Walk Eryri is now part of Mud and Routes which continues to provide more off beat routes and walks in Snowdonia and beyond. Dave has been exploring the hills of Eryri for over thirty years, and is a qualified Mountain Leader. Dave also established Walk up Snowdon, Walk up Scafell Pike and Walk up Ben Nevis just to mention a few.
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