Glyph of Warding and Tempest Cleric

Question

If I used a Glyph of Warding, used the Explosive Runes option, and set the damage type to lightning, could a Tempest Cleric use their Channel Divinity to maximize damage?

(Yes I know I would have to multiclass to get the Glyph of Warding spell)

Answer 1

Yes.

With the caveat of the fact you would need to be aware that it was dealing damage. Nothing about Glyph of Warding or the Channel Divinity feature impart any knowledge on the caster of if they are dealing damage. However it normally doesn't matter. Because if you are casting thunderwave, you know you are dealing thunder damage.

So if you cast glyph of warding on a door, and waited, watching for someone to trigger it, you would know just the moment to expend your Channel Divinity feature.

However if you cast glyph of warding on a chest in your basement, then left town and one night while you were asleep someone triggered it, you would gain no special knowledge that NOW was the time to activate it.

Answer 2

Probably only if you are aware the glyph is going off

In general, you can use metamagic or other effects that change how you cast spells to cast altered versions of the spell into the Glyph of Warding, and those spells will then be released with their altered or heightened effect.

However, the Channel Divinity: Destructive Wrath ability states:

Starting at 2nd level, you can use your Channel Divinity to wield the power of the storm with unchecked ferocity. When you roll lightning or thunder damage, you can use your Channel Divinity to deal maximum damage, instead of rolling.

This does not happen as you cast the spell, it happens as a modification you make when the spells effect happens. You would be casting the normal spell into the Glyph, and at that point you do not yet roll for damage, you only roll for damage when the spell is released. At the point of the release of the spell, you (normally) are not there to use your Channel Divinity to deal maximum damage instead of rolling for damage. You probably could if you were aware the glyph is going off, as there is no distance limit on the channeling.

I think this is not 100% clear cut -- your DM might also rule you can also do this whenever a spell goes off, as the ability does not say anything about you needing to be aware. But the way channeling is described, it sounds very much like something you consciously are doing to to wield the power of the storm with unchecked ferocity. And allowing this would create a way to know if the glyph was triggered or not (as it consumes your ability to channel), which you normally would not have.

PS. There is no need to multiclass, Glyph of Warding is on the cleric spell list.