The Astral Plane is a non-spacial non-plane of thought, memory, and psychic energy. Know as The Sea of the Mind. It is the final resting place of gods. It is a barren place with only rare bits of solid matter. The Astral Plane is unique in that it is infinitesimal instead of infinite; there is no space or time here. The souls of the newly dead from the Prime Plane pass through here on their way to the afterlife of the Outer Planes.
The Astral Plane seems, to the casual observer, to be a bleak and endless expanse of silver nothingness, interrupted only by the appearance of matter from other planes of existence. And such is indeed the case - for the most part. A few instances of natural disruption in this otherwise placid state do exist, though, sweeping across the Astral in a manner similar to weather patterns and storm fronts common to other planes of existence. As unexpected as they are rare, these occurrences of Astral 'weather' can prove extraordinarily dangerous to the unwary, and should be carefully studied by the experienced traveller.
- Limnfire appears as an ephemeral wave of pale green, translucent floating flames that sweeps forward onto those travelling the deep reaches of the Astral. Living creatures exposed to such report an odd and unpleasant sense of alternating heat and cold rushing across their bodies, neither so intense as to be immediately painful but extraordinarily disorienting and dangerous over the long term. In essence, characters exposed to limnfire suffer the dangers of both severe heat and severe cold, simultaneously. Natural or magical protections against both extremes of temperature are needed to block limnfire's effects.
A cloud of limnfire is typically 200-800 yards across, and moves through the Astral at a speed of 200 feet per round. As a result, it's commonly easily avoided by experienced travelers, though spotting it at a distance sufficient to change direction and avoid the material requires a DC 22 Spot check. A traveler who does enter a limnfire cloud finds that a certain amount of the stuff will permeate his clothing, armor, and other belongings - essentially lengthening exposure to limnfire for a duration of 1 minute per pound of equipment worn or carried. Removing clothing and equipment can serve to avoid any resulting environmental effects.
- Sanyc bubbles appear as an odd distortion in Astral space, looking almost like a freestanding soap film to the first-time observer. Entering a sanyc bubble can cause severe and debilitating hallucinations, casing vision and other perceptions to drastically smear and distort. Though such effects cannot actually change the appearance of any creature or object, in extreme instances they may blur perception to an extent sufficient to make observed creatures unrecognizable.
In game terms, victims of this effect must make a DC 24 Will save. If the check is failed, the victim suffers a -1 penalty to all Wisdom-based checks per point that the Will save was failed by, for a duration of 1-6 hours. Sanyc bubbles are typically no more than 20 yards across and are often smaller, but are nearly impossible to spot or avoid unless travellers know exactly what to look for.
- Kaelor fog is an opalescent mist that billows in mostly stationary cloudbanks, each about 50-200 yards in diameter. The stuff has an inexplicable effect on the subjective gravity of any travellers who pass within a quarter of a mile of a fogbank - first redefining their personal sense of 'down' to point towards the center of the fogbank, then cancelling their gravity entirely as they reach the center. A DC 12 Wisdom check is needed to regain control of one's gravitational direction while near a patch of kaelor fog; after entering the fog bank itself, a DC 17 Intelligence check is required to remember which direction one entered from.
Though only rarely deadly in its own right, kaelor fog has sometimes been used as a hunting blind for certain vicious and cunning predators of the Astral. The possibility also exists for a particularly weak-willed individual to be trapped within the kaelor fog, unable to regain control over their own gravity. And even if the above two fates are avoided, an encounter with kaelor fog can leave a traveller hopefully disoriented and lost. This is a navigational hazard that visitors to the Astral should steer well clear of.
- Hrem storms sweep in a broad, billowing front across the deeper reaches of the Silver Realm. Each appears as a long, comparatively thin tube of shimmering gold sparks, several miles long in a direction perpendicular to the axis of movement but extending only a hundred yards or so in each other direction. A typical hrem storm moves relatively slowly, covering only some 150 feet per round, but is often difficult to detour around.
Most creatures find passage through a hrem storm harmless, but the same is not true for spells and magical effects. The raw strength of any active spell or magical effect that passes through a hrem storm is halved for a duration of 1d6 hours after leaving the storm front behind (or until the effect expires, whichever happens first), but its duration is doubled. The same holds true for any spell cast while inside the hrem storm, should such a thing prove necessary. An Empowered or Maximized spell has its metamagic effects cancelled by the hrem storm's fury, but the base strength of the spell is not affected in this case. Highly magical beings may also find their life forces sapped or altered by exposure to a hrem storm, at the discretion of the GM.