The Mist is only 30' radius from Kurg, 20' high.
There were at least a dozen chariots, plus many more elves running behind, including calvary. You estimate a hundred or so in total, with many of them archers.
The Elves are most likely 80-120' beyond the Swamp. Not a good
situation, considering you would have to see them to charge, your movement will be impeded by the Muck and they most likely have several mages with them.
Nothing like 5 or 10 fireballs to brighten up your day woohoo!