Jeffrey,
Urgency is the measure of recent changes in the Lead's Score. More activity over a shorter period creates more flames.
These scores are held in Urgency (0-1) and Relative Urgency (0-3).
So in theory, you could set a flow to adjust all of these leads to 0 and that should take care of the fire. I'd test that on ONE lead first though.
Somewhere, buried deep in this site, is a calculation of how the urgency works. I can't find it in my guide so that's the best of my knowledge.