What happens when spiderwebs are set alight?
Though page 69 of the DMG lists spiderwebs as a special terrain it doesn't talk about the effects of fire.
I'm about to run in encounter with a LOT of webs, and I'm sure the fire elementalist will set it all aflame, if possible.
I can't find the official rules for how fast it burns (if at all) and how much damage it does to anything within (spiders?) and if there is a saving throw...