The Maelstrom is an unusually stable and unusually powerful mana storm that has raged in approximately the same place in the Badlands for at least hundreds of years. Historical accounts suggest that the Maelstrom or a storm like it has raged on around the Badlands and the Great Lake area for even longer than that, though not in the current location. The Maelstrom itself averages around 20 miles in diameter, though on its worst days it can grow to 60 miles or more.
The orcs around the Maelstrom have developed a categorization system for the intensity of the storm, measured every morning. Camps nearby hang between one and five flags from a high post on the captain's tent indicating the relative power of the storm as reported by a magic-capable scouting party. The scouting party casts a long-duration version of arcane sight optimized for analyzing mana storms, then marches to within sighting distance of the edge of the storm. They take "measurements" for at least half an hour, then return, and this must be completed before midmorning call (roughly 9 AM).
The PCs experienced a Category 3 Maelstrom during their first foray into the storm. During a category 3 event, the storm manipulates available magical energy, potentially draining or empowering spells and magical abilities cast or used within its borders. The effects vary widely, but if enough magical energy is drained from an attempt, the spell fails. Too much additional energy dumped into an attempt can result in damage to the channeling item or to the spellcaster.
Spellcasters who suffer feedback from failed or overcharged spells during a category three event begin to lose access to their higher levels of spells due to mana burnout. Short-term exposure results in many days of recovery before the spellcasters can manage to memorize or channel the energies of their top few levels of spells. Spellcasters who suffer sufficient burnout to lose access to all spells may even suffer additional effects.