Glacial Wahianoa Valley

The Wahianoa valley was once filled to the brim by a large flank glacier from Mount Ruapehu. A glacier has occupied this valley for at least the last glaciation, probably the last two, forming the very prominent moraine ridges visible from the Desert Road. There are substantial blobs of lava in the head of the valley (just below the snow in the photos) which have finely-jointed columns indicating some interaction with the former glacier. These lavas are dated to about 18 thousand years old, but most other lava has been excluded from the valley by the thick ice. Younger lava has not been able to get into the valley because the vent (under Crater Lake) is now on the other side of a high ridge. This is why the valley is still so deep and retains its classic glacial U shaped profile - it hasn't been filled up with lava flows.

How thick would the ice have been? The lateral moraines were created when rock debris slide down off the sides of the glacier so the ice was at least as high as the moraine walls. Can you imagine the valley filled by the glacier? Some lava would have been burrowing in around the sides of the ice to create those lava blobs at the head of the valley. What has happened to the glacier since the ice age?