Blue Mountain

Everyone remembers the darkest year since the Fourth Reckoning. Skies across Tanish were covered in ashy grey, making agriculture difficult and food scarce. The mines in Karika Valley that had collapsed and killed hundreds were still inaccessible, cutting off their access to their primary international export. Fish in the Retays River inexplicably died.
The reason, the Great Prince assured them, was because they had angered the gods. They had let the gods drift from their minds and not worshipped them correctly, and so Entu had covered the sky, judging them not worthy of receiving his light. All they could do was beg forgiveness from the gods and hope the skies cleared. Each province provided a child, picked from the upper classes and chosen for their physical perfection and beauty, to be sacrificed at the The New Temple of Entu. When the sacrifices were done and temples and shrines throughout the kingdom packed every day with repentant masses, they waited for the gods to forgive them.
Eventually, the smoke stopped pouring from Blue Mountain and the ash that had rained across the kingdom for months drifted away across the desert. Entu was pleased with their sacrifice, and returned the sun to them.

Geography

Of course, it wasn't the gods who filled the sky with ash. It was the stratovolcano on the eastern edge of the kingdom formed from the South Kaabara Rift.
Blue Mountain is an 11,384 foot active volcano, though its last eruption was the above referenced Dark Year in 311. Its peak has snow in the winter and late autumn, but not in the summer. The Retays River is fed from a spring on its side, which swells in the summer with the melting of snow. Sometimes, however, sulphur vents leak into the river and kill off the local fish.

Type

Volcano