by jmarkb » Fri Aug 16, 2013 10:57 am
Getting from Sgurr na Stri to Loch Coruisk should be fine: just head back north to the path, then follow the Allt a' Choire Riabhaich down to the Loch.
Crossing the ridge via the Bealach na Glaic Moire is not technical but there will be plenty of scree and steep rocky ground. On the way up to the col from Coruisk, take the left hand side of a rocky rib, up scree and passing a spring about 100m below the ridge. The main problem is the route finding on the descent into Coire a' Mhadaidh: a direct line will take you onto steep and dangerous slabs. Instead, you need to traverse NE-ish under Bidein DnR for 300-400m until a steep scree gully leads down into the Coire. The path marked on the OS 1:25000 map shows roughly the right line, but don't expect to find any traces of it on the ground. This section could be very tricky in poor visibility: there are a couple of false gully lines before the correct one.
An alternative way across the ridge would be to head for Harta Coire, over Bealach Harta (the first col NE of Bidein DnR) and down into Coire Tairneilear: also rough screes and no path, but easier route finding.
The easiest crossing of the ridge is the Bealach Coire na Banachdich, but that takes you rather out of your way for a return to Slig.
Please note, I haven't done your proposed route myself: this is all info from guidebooks, but I hope it helps!
None of the ridge crossings are well travelled routes, so it's a fairly serious trip to do on your own, if that's the plan...