With the caveat that what I say in this post is based on the way it was done in the early '60s:
The cooling elements under the arena floor pumped brine at below freezing temperatures to keep the ice stable in what was a relatively warm building, but since we are dealing with salt water the temperature could be raised to much higher ranges. We never had to do that in the normal course of events but I remember one night after a hockey game we were doing a setup for a circus starting the next day. The setup included ice out, scrub and dry the floor, dasher boards out, and a base of dirt laid on the floor before the site was handed off to the circus peeps (the riggers / stagehands). It was late in the season and the ice was fairly thick 2½", so toward the end of the third period we started heating the brine to speed up the ice-out.
Why bother warming the ice up at all. Soft ice tends to be a little slower than 'good' ice but it does hold an edge a little better and I am told that figure skaters prefer the ice a little soft. In the normal range of indoor surfaces there is really not that much difference and the figure skater and hockey players pretty much can deal with what the conditions are. Long track speed skaters do prefer a surface that is a on the hard side. Hard ice can be an issue though as it tends to be a little brittle. If it gets cold and hard enough in theory it becomes very hard to skate on. This would never happen indoors but I suppose it could occur outside and it was pretty damned cold last night in Minneapolis. (there is a theory of why ice skating works that involves melting the ice beneath the edges not sure it is credible)
We are supposed to get a few inches on Wednesday and Thursday, but it shouldn't be like this.
