Haskell Strait refers to the ocean passage in southern McMurdo Sound, running between Cape Armitage, Ross Island and Cape Spencer-Smith, White Island, Antarctica. Oceanographically, it separates McMurdo Sound from the ocean basin (ice shelf cavity) beneath the Ross Ice Shelf. The Strait itself is around 25 km wide and in places over 900 m deep. Currents of nearly half a knot have been measured in the Strait, although typical flows are lower. It is mostly covered by the ice of the McMurdo Ice Shelf and fast ice in southern McMurdo Sound. On rare occasions sea-ice breakout exposes the north-west corner of the Strait which becomes navigable and vessels can actually moor off Scott Base.