The portal storm has a lot to do with Terra’s origin and diverse history. it can appear in four shapes and sizes.
Classic portals are around 7 feet tall and 4 feet wide. they usually glow white, and are made for a person(s) to willingly pass through. Like most other portals they collapse after the desired person or people have passed through. Most commonly these are used to allow a single hero or a small tribe to be introduced into Terra for whatever reason. these portals seem to be at 100% Elphion’s control. All classic portals are one way.
Continental portals can vary in size greatly, but more often than not they are as large as countries. They suck in giant masses of land and place them somewhere in Terra. All land that is now on Terra arrived in this fashion. These portals are not under Elphion’s control at all and happen at random, about every 1000 years or so. All continental portals are one way.
reversible portals are similar to Classic portals in size and shape, but differ in design. A reversible portal can go both ways (to and fro) and have only been used to travel from Terra to The tomb of heroes. Elphion has no “direct” control over reversible portals, the master of these is the watcher of the tomb.
Spear portals, like reversible portals, are exclusive to the Tomb of heroes. How they differ however is that Spear portals “suck in” an object from anywhere on Terra and add it to the massive collection of weapons stored in the Tomb. The watcher also controls these, and as far as we know they are only one-way. A sword has never tried to jump back through the portal.