My biggest nightmare jaunt, was some years ago.
I am a fair weather chap, so decided on a full circuit of the Carneddau, parking in Cwm Eigiau.
Weather was superb, a bit cloudy, but high above the 3000ft plateau, so i was in for a great adventure.
On recollection I think i used the valley approaching Fynnon llyfnant below llewellyn, discovering fresh bits of plane wreckage on my way.
As i was walking up those very annoying stony bits towards Llewellyn's main plateau, a sea mist from the Gerlan direction washed in from the coast.
It was majestic to look at, but within minutes i was enveloped in the legendary Carneddau mist.
Taking a bearing on my compass was useless, as i could not see any known feature to navigate by.
As Neil discovered, i found myself traversing very treacherous ground.
A few weeks later, on a return visit, i had found the route towards Yr Ellen, and it was very steep and scary in the mist, it looked far more severe in poor visibility, and because i knew i was on tricky ground, i continued back the way i came, to continue going around in circles for close on to an hour.
The only route to safety i could eventually find, was towards the Ogwen valley, down the Fynnon Llygwy road, miles away from Eigiau.
A phone call to a friend , and several hours later, i got back to Eigiau, but it was an epic traverse of the Carneddau, well and truly spoilt.