I'm a great believer in the Föhn effect when it comes to choosing where to hike or cycle in and around the Dublin and Wicklow Mountains. Complex meteorology aside, this describes the alteration in moisture content and temperature of an airmass after crossing over a mountain range.
Ok, our mountains are not exactly the Rockies, or the European or New Zealand Alps, where the effects are profound, but, in their own minor way, they can often give perceptibly better weather on their lee (such as warmer air, less rain and a higher cloud base) than on their windward sides, and the longer the "fetch" of the wind over the mountains, the more beneficial the effect.
And so on a blustery October day of unstable south easterlies, the northwest corner of the mountains was my choice, and more specifically, Seahan, Seefingan and Seefin – Dublin and Wicklow’s highest “holy mountains”.
These ancient rounded mountains would have been the Croagh Patricks or Brandons of their day, with the local hunter-gatherer-turned-farming communities of 5,000 years ago perceiving a spirituality on their high summits, and constructing massive megalithic tombs there – their efforts much later attributed to heroes of Celtic folklore, as the "modern" names attest.
The best way to visit these mountains and their cairns is via a nice circuit of the Kilbride Rifle Range, taking in Seahan (648m), Corrig (618m), Seefingan (724m) and Seefin (621m).
I parked near the entrance to the Range, did a short 2km road walk northwards to the highest point between Butter mountain and Seahan where I entered the Coillte plantation (roughly cleared) on the right.
Within the plantation, I followed clear tracks and paths and some heather walking for about a kilometre, to the summit of Seahan.
This was clearly the holiest of the holy mountains, boasting a collection of tombs, including two vast cairns, one of which may have been quarried or cannibalised in the past.
Then it was on over Corrig mountain, which seems to have received no prehistoric attention, and along a wide, boggy but easy ridge to Seefingan, which most certainly did.
A massive stone cairn, its unexcavated secrets locked within it, and the deep encroaching bog around it, sits curiously about 20m in altitude below the rounded summit – so as to maximise the impact on the skyline for those early farming communities in Wicklow and Kildare.
Then it was on to Seefin, the last of the prehistoric holy mountains on my route, with its excavated and equally massive cairn, again pitched just off the summit as with Seefingan.
That enigmatic 5,000-year-old gift from our Neolithic ancestors afforded me a final moment to observe the Föhn effect in operation as the 75-year-old Poulaphouca Reservoir in the mountain lee reflected an increasingly breaking sky of dancing sunbeams.
An easy descent by the edge of the plantation and a short road walk to the car completed a very interesting and satisfying walk.
Map:
OS Discovery Series sheet, number 56
Start/finish:
near entrance to the Kilbride Rifle Range, Co Wicklow (about 4km off the R759)
Time/effort:
about 500m of climbing, 11km overall; four to five hours
Suitability:
moderate level of fitness needed, and knowledge of mountain navigation
