I think the calcium chloride is to keep the "snow and freezing rain" from forming an ice dam on Sinsull's roof. She has a leak. Calcium chloride would lower the freezing temperature of water just like sodium chloride (regular salt) does, but it wouldn't "all disolve away" as fast. Don't quote me on it though. I'm just a dumb old Florida Cracker. Don't know much about ice and snow. "Thank God!"