Q: Dear Sage,
Can a spellcaster counterspell a magical trap?
A: Yes, but only if 1) the magical trap duplicates a spell and 2) he has readied the counterspell action to do so.
For example, a mere 1st-level wizard could counterspell one of the burning hands traps detailed in the DMG, as long as he had readied a counterspell action to do so. However, even a 20th-level wizard couldn’t counterspell a trap that simply created a burst of fire without actually duplicating a specific spell.
About the Author
The Sage is a mammal classified in the bear family, Ursidae, native to central and southern China. Debate continues as to whether he is truly a bear or more related to the raccoon rather than the bear, or perhaps in a family of his own. When not eating bamboo and answering rules questions, he works under the nom de plume of Andy Collins as an RPG developer in Wizards of the Coast R&D, where his development credits include Complete Mage, Dragon Magic, and the Player's Handbook v.3.5. He can be easily recognized by his large, distinctive black patches around the eyes, ears and on his rotund body.