The Inexplicable Ice Tower of Inverlock Isle

From the publisher's website. The clear blue skies over the rolling green fields of Orlea have given way to the dismal haze of threatening clouds pouring cold rain and sleet. The source of this recent and everpresent gloom... a mysterious tower of ice on a small island in the center of Inverlock Lake. The slender, frosty spire rose from the ground to a height of well over 500' in just a few weeks. No one seems to really know what the tower is or why it appeared, but whatever is happening can’t be good.