Known Changes on the Planes

Outlands

The broken Spire is visible from any part in the outlands, Sigil can be seen hanging precariously from the top of the collapsed rock.

Magic works near the Spire, but many say it’s going wild now. Spellcasters who approach the center of the Outlands claim to feel a tingling sensation, which grows to insufferable levels the more they approach. Other reports claim that they feel their magic grow stronger.

The Gate-Town of Sylvania, which leads to Arborea, formed a planar rift on the sky that sent river Oceanus right through the city. This flooded nearly half of it and the rift remains there, constantly spewing water, which luckily flows away from the city and spills out from the edge of the Outlands. The citizens of Sylvania were quick to make a port and design specific spells that would allow ships to travel upwards and through the rift, thus making Sylvania a port city. More than half of the valley Sylvania was in has become a lake.

Tir-Na-Og fell into a rift, but divinations say the entire place fell unharmed. No mention of its denizens, though.

Elemental Planes

The fabled City of Brass is no more. It has sunk inside the lava and the area in which it sunk is now a frozen ice lake right in the midst of the elemental plane of fire, that does not seem to melt.

A new, large, elemental pocket has been formed on the borders of the para-elemental plane of lightning. Molten lava appears out of nowhere constantly, cools off and is then struck by the natural lightning of the plane, thus forming an area of twirling, volcanic debris with unusual properties. The source of the lava has not been discovered yet.

Known Changes on the Planes

Planescape - Era of Shifting Portals Igrith