Fog on the brine
Overview
A wonderful, unsettling phenomenon has crept without warning over the surface of the Bay of Catazaar. It appears one evening just as the sun dips below the horizon on the last night of the half-moon before the Equinox. A curling, roiling, pearlescent mist rises from the surface of the sea - a bank of nigh impenetrable Autumnal fog. Unlike a natural fog bank, however, the swirling mist rises no more than perhaps six or seven feet from the surface of the water. The fog is mildly phosphoresent, glowing with a faint iridescent radiance that ebbs and flows and is eerily hypnotic. From a distance, it appears almost solid - especially by moonlight - but anyone stepping out onto it drops through into the water below.
The fog appears simultaneously along the coasts of Feroz, Madruga, Sarvos, Necropolis, Redoubt, and Spiral. It seems to stretch out to sea, and looks to cover the entire Bay of Catazaar, as if someone has pulled the clouds down from the sky and smeared them across the surface of the Bay. It is greeted with a mix of wonder, excitement, and suspicion. In a few places in Sarvos and the Brass Coast, impromptu parties take place that stretch on into the night - enterprising boat and ship owners taking revelers out to explore the ebb and flow of the cloudstuff under a spectacularly clear night sky.
The next morning, the fog is still there. By daylight, it looks ... sullen. Gloomy. It dampens sound oddly, and it makes the lives of the fisherfolk in particular difficult and unpleasant. There are a few accidents. The sun does nothing to thin it; it is as impenetrable and pale at noon as it was at midnight. More people begin to be concerned. The first trading ships from foreign shores arrive in the ports of the Empire and report that the fog begins a little over a dozen miles to the south of the tip of Feroz, and does indeed appear to spread across the entire northern half of the Bay of Catazaar.
It is primarily a problem for smaller boats; trading ships pass through the fog without too much difficulty - as long as they know the waters. The fog hides any number of obstacles and hazards, including reefs, shallow waters, and jagged rocks. Several foreign ships, new to Imperial waters, suffer upsets as a consequence.
The captains and crew of several Imperial trading vessels describe the experience of being in the fog, away from sight of land, as if they are sailing through the sky, across a vista of clouds.The mist does not impede them - if anything, the fact it seems to be coinciding with extremely clear night skies that make it much easier to navigate by the stars at night.
The fog shows no signs of going away.
Significance
This eerie magical fog persists still. It does not spread inland - occasionally it will lap over onto the coast but it quickly withdraws. It flows where the sea flows - and it seems to extend only over salt water. While it chokes the mouths of the four great rivers, it does not extend along them. Strong winds whip the surface of the fog into concupiscent curds, but do not break it apart or even thin it.
So far, the only information the magicians of the Empire have been able to gather with their detect magic incantations is that this is a magical effect of the Night realm, of 30th magnitude, that conceals information - including information about it's own nature and properties. Most magicians agree that the effect could be examined with a suitable powerful performance of a ritual such as The Eye of the High Places, targetting one of the effected territories.