Gleann Bhaltos (Valtos Glen) is a striking example of a glacial meltwater channel which runs between the villages of Timsgearraidh in the west and Miabhaig in the east.

Glaciation has been the major factor in shaping Uig's landscape. Gleann Bhaltos was formed by water from melting ice sheets. It extends to around 2.5 kilometres in length. With no alternative exit route, the large volume of meltwater carried sandy outwash material from the area of the esker ridge, that can be clearly seen at Carnais today. (GR 034 315)

At this time, the sands and gravel of the esker would have extended right across Uig Bay to Cradhlastadh where smaller areas of similar deposits can also be found today. The actions of rivers and the sea have eroded these deposits to produce the vast expanse of sands that form Uig Bay.

The outwash sands carried eastwards by the meltwater along Gleann Bhaltos were deposited in Loch Roag. So it is glaciation that we can thank for the area's beautiful beaches and machair landscapes.

Gleann Bhaltos provides a natural routeway and is followed by the B8011. On the north side of the glen there are scree slopes which were quarried in the past, resulting in scarring of the landscape. At the south-east, there is a small area of coniferous forest which was planted in the 1960's, the glen affording shelter from the salt-laden winds.  

After periods of heavy rain, many waterfalls can be seen running down the steep sides of the glen which has now been designated as an SSSI (Site of Special Scientific Interest) and is therefore protected from further damage. A walk along the glen following the B8011 will take around 50 minutes.