[2] The two spires (North and South) are virtually one granite massif, split by a deep cleft formed by jointing and erosion.

Early Winters Spires are located in the marine west coast climate zone of western North America.

[5] In addition, small fragments of the oceanic and continental lithosphere called terranes created the North Cascades about 50 million years ago.

[5] During the Pleistocene period dating back over two million years ago, glaciation advancing and retreating repeatedly scoured the landscape leaving deposits of rock debris.

Uplift and faulting in combination with glaciation have been the dominant processes which have created the tall peaks and deep valleys of the North Cascades area.