It is not enough to see, we must do

Proof is in the pudding.  This week, temperatures in Arkansas and around the nation have been in the way sub freezing. (ie the infamous Polar Vortex.)  Some folks said it was not cold enough in Arkansas to do this particular thing... throw boiling water into the air and have it rain down ice...but the proof is in the pudding.  I see the steam, and heard the chucks of ice fall on the lawn.

Anyone know why this should work with boiling water and not with cold.

Ps.  Outdoor temp was about 15 degrees F.