Sinister Gully is one of the most popular routes in Snowdonia and combined with Bristly Ridge, is one of the classic scrambling lines in the UK.
I’ve already published a guide and video for those who wish to scramble up the neighbouring Dexter Gully but Sinister is the route most people will take but how difficult is it? What can you expect?
Keep reading to find out.
Approach – How to Get to Bristly Ridge and Sinister Gully
My parking map displays over 250 spaces, many of them in laybys and free car parks.
I almost always scramble up Tryfan’s North Ridge first and then descend via the south ridge to the col (Bwlch Tryfan on maps) before going up one of the gullies and onto Bristly Ridge – this longer route makes more a day of it and the Tryfan/Bristly Ridge combo is a popular pairing.
If you’d prefer a more direct route, try one of these:
Imagery © 2023 Google, Airbus, Bluesky, Infoterra, COWI, Cnes/Airbus, Getmapping PLC, Landset, Maxar Technologies
From Ogwen Cottage
Take the path left of the toilet block near Ogwen Cottage up the wide steps and after a short distance, take the left fork and follow over a footbridge. After 200 metres or so, the path will curve rightwards, take a slightly narrower path to the left, ascend a steep path next to and then over a stream up to the left bank of Llyn Bochlwyd.
Continue to the pass where you’ll see a stone wall in front of you, Tryfan’s south ridge to your left and Bristly Ridge to your right.
From Gwern Gof Uchaf Campsite
Park in the long layby below Tryfan and take the path between the A5 and Tryfan up to the rear of the campsite, go over the steps and take a right, following the obvious path to the left of Little Tryfan (Tryfan Bach) – a popular climbing area.
As the path rises, go over the steps at the top and follow the path to Bwlch Tryfan – a col at the foot of Tryfan’s south ridge, which marks the start of the route up Sinister Gully and Bristly Ridge.
Find The Man-Made Retaining Wall
A short man-made retaining wall separates Sinister Gully from Dexter Gully. You’ll need to go over the wall to enter Sinister Gully (see photo).
How to Scramble Sinister Gully
Sinister Gully is far more stable than the neighbouring Dexter Gully, and it’s mostly solid rocks and good holds all the way up to the top.
The start is a series of steps that are relatively easy to scramble up; the going here is fun but never goes beyond a grade 1 if you stay in the gully bed.
Alan scrambling up the start of Sinister Gully.
Looking down at the mid-section of Sinister Gully.
The Crux of the route is a steep section that I’ve heard being called “the wall” on several occasions.
It’s not a wall at all, just two large rocks jammed next to each other with a very narrow gap between them:
The crux of the entire route.
The best way to get over this section is to go straight up the middle, making use of the solid footholds available.
The clamber over the top will likely be less than gracious and it’s somewhat more difficult in the wet, although this is a popular route and the rocks are mostly clean.
The Avoidance Line
The steep section can be easily bypassed by taking a line out to the left. The scrambling here is easier and after a few metres, you can rejoin the main gully, above the tricky wall.
Alan taking the left avoidance line.
Topping Out of Sinister Gully
The top section of Sinister Gully widens and is shallower but still fun to ascend.
From here, the views of Tryfan look impressive.
The top section is broader and slightly shallower
Descents and Continuation
I don’t recommend descending Sinister Gully as the steep section could be problematic, although, for an experienced scrambler, the avoidance line is doable in reverse.
I certainly don’t recommend descending via Dexter Gully next door as that route is full of loose stones and mud.
Most scramblers continue up onto Bristly Ridge proper and then onto Glyder Fach. Sinister Gully isn’t usually scrambled without a continuation and from Glyder Fach, there are dozens of routes one can take.
Comparing Sinister Gully to Dexter Gully – Which Should You Choose?
If you’ve never scrambled up Bristly Ridge before, I suggest going up Sinister Gully, the handholds are more solid, and there’s less sludge and fewer loose stones. The one steep wall in Sinister can also be avoided, now you have the know-how.
While both gullies are a grade 1 scramble, Sinister is more enjoyable and is far more popular.
Don’t be put off by the unusual names; sinister is Latin for left or left side while dexter is Latin for right, or right side (source).
For those of you who have already ascended Sinister, check out the photos and videos of Dexter Gully here.
Route Profile and More Info
Scrambling Grade: Grade 1.
Navigation: Literally straightforward once you’re in the gully. The approach could be problematic in poor weather but the gully is easy to follow and short.
Dangers: The steep section three-quarters of the way up is the most obvious hazard. Otherwise, the risks and dangers are as you would expect from a grade 1 route. Some rocks may become slimy in the winter but holds are solid in the summer due to the number of people who use this route.
Approach Time: 1hr 15m max.
Ascent Time: 15 mins (exc the Bristly Ridge continuation which is quite an undertaking).
Popularity: Very popular, the most popular route onto Bristly Ridge.
Fun Rating: 9/10.
My Dislikes: It’s a short gully and over way too soon.
Kit List: My kit list is here.
I’ve been up Sinister Gully more times than I can remember and it’s one of my favourite lines.
I initially found this route in a guidebook called “Scrambles in Snowdonia” by Steve Ashton. It was first published back in 1980 but has been updated several times since, most recently in 2017.
If you want a guidebook to take with you on scrambles, this compact book is the best.
Recommended Guide Book:
Scrambles in Snowdonia by Steve Ashton (#ad)
About Daniel Woodley
This description of Sinister Gully was created by Daniel Woodley, aka The Bald Scrambler.
From walking along beaches and kayaking down rivers to making his way up mountains and even jumping out of planes, Daniel has a love of the outdoors but scrambling is his real passion.
Daniel Woodley aka The Bald Scrambler