Kirn of Skroo west tunnel (S entrance)

Kirn of Skroo gloup. Reportedly connected to the sea by a tunnel to the N linking to GSG30. This gives a tunnel length of ~70 m measured on GIS. Image from rim of gloup shows the N tunnel leading off with light penetrating through from the seaward end. The floor of the tunnel is shallow with many boulders breaking the surface (>0.8 mACD). Well illuminated with boulders coated in coralline crusts. Also reportedly connected to sea by a tunnel leading to the NE to reach the sea at GSG31. This gives a tunnel length of ~100 m measured on GIS. Image from rim of gloup shows the NE tunnel leading off but does not provide a clear view within the tunnel. [Report 1145]

"The Kirn o' Skroo is a partially-collapsed cave where the sea roars in via an 80m long subterranean passage." (1)

A large hole having a subterraneous passage to the sea ⅛ of a mile north east of the south end of Urashield. (2)

The OS shows two sea cave tunnels with entrances HZ 22247 73957 and HZ 22305 73912 which converge to HZ 22241 73889. The 1st Ed - and the above description indicates that the Kirn (centred HZ 22242 73871, approx. 40 - 60 m diameter) is a large gloup (collapsed roof).

The pattern of the collapse seen from aerial photographs suggests there may have been a secondary collapse at HZ 22210 73824.

Notes: The early OS maps suggest there is a short open space between the inner ends of the two tunnels. This is confirmed by photo 1 ie the tunnels are separate.

The above NGR is based on a) the OS showing this entrance in the SE corner of the geo b) Bing Aerial indicating something similar, but not clearly c) the photo of the S entrance indicating that the tunnel follows the strike of the sandstone bedding ie 035 degrees based on the east side of Cristal Kame.

Do not confuse with the Kiln of Skroo, a smaller collapse slightly to the north-west but as yet not connected to any known sea cave.

Links and Resources:

(1) www.shetlandvisitor.com/fair-isle .
(2) scotlandsplaces.gov.uk/digital-volumes/ordnance-survey-name-books/shetland-os-name-books-1877-187....
Shetland, Sheet LXIX (includes: Dunrossness), Survey date: 1878 Publication date: 1881. Marked as Natural Arches.
1st Ed OS 6 in zoomed in to show Kirn of Skroo and these tunnels.
Photo 1 looking down about NE into the gloup. This entrance is marked 'Tunnel to N' although it actually runs about 035 (NE by N). Note that this tunnel side walls are aligned with the sandstone bedding and thus the direction of the tunnel is likely to be the same as the waterline of the east side of Cristal Kame. p192 of FI Caves (GSG version) an annexe to Report 1145.
Photo 2 is a zoomed version of Photo 1 showing this entrance. p193 of FI Caves (GSG version) an annexe to Report 1145.
Map 17 has this entrance marked CI79. The north entrance is marked GSG30. p186 of FI Caves (GSG version) an annexe of Report 1145.
Bing Aerial giving a view from directly above. This cave tunnel entrance is marked CI79. The NE entrance is marked GSG31.
Rpt 1145 Harries, D.B., Purcell, A., Moore, C.G., Lyndon A.R., Porter, J.S., Saunders, G.R. and Hume, C.L. 2024. Distribution mapping and baseline monitoring survey of sea caves around Fair Isle. NatureScot Research Report 1145.
Canmore ID 330256. Suggests the upper area may have been quarried.
www.geograph.org.uk/photo/3079994 shows the gloup which is very unlikely to be a blowhole - if you mean that water spout out from it. This is because the tunnels are long and relatively narrow - so only limited wave power can get through into what is an inverted funnel. It is very wide compared to the tunnel area.

This entry was last updated: 2026-01-28 15:21:48

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NGR:	HZ 22243 73897
WGS84:	59.55037, -1.60833
Length:	77 m
Vert. Range:	Not recorded
Altitude:	0 m
Geology:	Wardhill Sandstone Formation
Tags:	Shake
Registry:	main

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