Kinabalu is a huge granite dome that was pushed up from the earth’s crust as molten rock millions of years ago. The accompanying upheavals, folding and faulting formed the surrounding sedimentary shale and sandstones into the nearby mountain ranges of Crocker and Trus Madi. Mount Kinabalu is a very young mountain as the granite cooled and hardened only about 10 million years ago. During the ice ages of about 100,000 years ago, the massive mountain was covered by huge sheets of ice and glaciers which flowed down its slopes, scouring its surface in the process. Only the sharp summit peaks stood out above the ice.

The icecap is bought to have melted about 3000 years ago, but the glacier-smoothed slopes of the summit plateau and the jagged ice-plucked peaks bear mute witness to its frozen past. Today wind and rain continue the erosion process known as exfoliation, caused by alternating high and low temperatures. Clusters of small circular pits in the rock slabs, a few centimeters deep, are the result of continuing frost action. Other features that visitors can notice on the summit plateau are long white rock bands or dykes that intruded through cracks in the granite massif as it rose. No snow falls on the mountain today and there are rare reports of ice forming in the little rock pool at the summit. (Called “Sacrifice pool” or “wishing pool”, it was a traditional site of offerings to the mountain spirits early.)

Because of the mountain’s relative youth, the terrain is steep and precipitous with knife-edge ridges. Landslides are common. Rainfall is high and often torrential, with an average of about 2700 millimeters a year recorded at the Park Headquarters (1563 meters/5128 feet), around 3300 millimeters at Panar Laban (3270 meters/10728 feet), and about 2500 millimeters at the Poring Hot Springs (550 meters/1805 feet). There are many waterfalls, like Kadamaian waterfall on the southern flank of the mountain is one of most spectacular in wet weather, when sheets of rain slide across the summit plateau and pour down its side.