In November 2013, a colleague of mine, Nic Cullen of Otago University, was part of an expedition to climb Aoraki/Mt Cook, the highest mountain in New Zealand, in order to remeasure its current summit elevation.
In the early morning of 14 December 1991, 12 million cubic metres of Aoraki/Mt Cook, in the Southern Alps, collapsed and roared down the ice fields of the east face. It then plunged to the Tasman Glacier on the valley floor. The rock avalanche travelled 7.5 km at an average speed of 200 km/hour. No property was damaged and there were no fatalities, but climbers on the mountain had a close call. The edge of the slide passed less than 300 m from Plateau Hut as they were readying themselves for an attempt on the summit.
Photo after the landslide (also from Te Ara)
Aerial photography-based calculations performed by Otago National School of Surveying researcher Dr Pascal Sirguey and Masters student Sebastian Vivero indicated that the summit height had changed and in response to this the expedition was arranged to remeasure the summit with high precision GPS instrumentation as a field validation of the photogrammetry work.
For more information you can read the Otago University article about the expedition, or the excellent project webpage, and I also recommend watching the very nice video they made about the expedition:
Out of respect of the cultural significance of this mountain the research team did not step on the summit, but used GPS measurements from just below the summit to constrain a photogrammetric model of the mountain.
The official summit height of Aoraki / Mt Cook is now: 3,724m