This page explains how to find the Suma Sahma shrine.
How to Find the Shrine
Go to Wasteland Tower, then go southeast along the mountains. Continue traveling southward on the mountaintops to reach Mount Granajh. On top of Mount Granajh, read the diary in the ruined cabin to start the shrine quest.
Then start a fire if you have a source of fire and wait until noon. Pick up a snowball and go south from the cabin to see a shrine pedestal on the wall. Hold the snowball and wait until 4:00. The pedestal will glow orange. Move around so the shadow of the snowball is centered on the pedestal. The shrine will appear nearby.
About the Shrine
The chest in the shrine contains a Moonlight Scimitar.