Mount Hood Shadow Spike

Mount Hood Shadow & Spike ~ Taken by Vincenzo Miceli a short distance below the summit of Mount Hood, Oregon. The mountain casts a long shadow through the air. Above it is a strange upwards and rightwards pointing spike. ©Vincenzo Miceli, shown with permission

Upward shadow spikes are never seen on a mountain summit. You must be a little below the summit.

To understand spikes, imagine the mountain sliced into two. One mountain below you and another one above.

Most mountains have triangular shadows regardless of their profile. What you see is a perspective view along a shadow tube through the air and extending several miles. It is roughly parallel but from one end and near its edge it appears triangular.

The mountain below you produces an upward pointing triangular shadow.

The mountain above you makes another triangular shadow but pointing downwards. If you are on one side of the mountain relative to the sunlight then the shadow appears as a spike pointing in the opposite direction. The closer to the summit the smaller is the mountain above you and the smaller and fainter is its shadow.