Lake Mavis

Lake Mavis is an alpine lake in a basin beneath Mt Oates’s steep palisades, reached on foot from Goat Pass on the Mingha-Deception route. It’s a rewarding add-on if you’re already at the pass with enough time and safe conditions; the climb is steep and largely unmarked, so it’s not a casual detour.

The spur climbs through steep tussock and scree before following cairns along the ridge. The route is faint and easy to lose, and it steepens again near the lake’s outlet waterfall. Allow about two hours for the side trip; a recent overnight account found the main rise alone took about an hour and fifteen minutes.

The lake is reached as part of a longer tramp, not from a roadside stop. Greyneys Shelter, about 5 km south of Arthur’s Pass village, is one approach into the Mingha Valley; the route passes river flats and beech forest before opening into alpine scrub and tussock at Goat Pass. River-crossing skills and previous backcountry experience are essential. Rivers can rise quickly, and the Deception section can involve many crossings, so don’t go in high water or when bad weather is forecast. The area has avalanche exposure when snow remains, including outside winter. Dogs aren’t allowed on the route.

Mt Oates rises above the lake, and a waterfall spills from its outlet. Snow and ice sometimes fall into the water and float on the surface, a seasonal sight rather than a sure thing. On a clear day, the view can reach across the Arthur’s Pass peaks to Mt Rolleston. When the surface is still, the mountains reflect in the lake, making the shore a good place to pause with the whole basin in frame.

Whio may be seen around the turquoise pools, rapids and waterfalls in Mingha Gorge. Kea may also visit the campsite. Both are possibilities, not guarantees, and the whio sightings are reported along the approach rather than specifically at the lake.