I just checked Whitetail's cams (at 10:44 p.m.) and have also checked on them a couple times this evening, and it looks like every snow gun there is running -- is it possible you were looking at a cached image? Whitetail's cams automatically rotate every now and then and sometimes fog/ice up, making it difficult to see what's going on, but I can clearly see snowguns running in force on all the major slopes except the top of the bunny slope. The bunny slope already has very good coverage, and they try to limit snowmaking on that slope during operating hours (they only closed 45 minutes ago) to prevent beginners from being blasted with snow. But it looks like a virtual blizzard to me and they had lots of guns going this evening when I last checked, too. Probably the cams were rotated to uninteresting spots when you checked.
In terms of Wisp, it is much harder to tell on their webcams right now whether snowmaking is going on. But I am happy to see lots of white snow on all the slopes!
It is 10:30 Thurs. evening and most ski areas are really pumping out the snow: Liberty, Roundtop, Wintergreen, 7Springs, etc. But the cams at WISP and Whitetail show no snow being made on the slopes...on the tubing run yes, but the slopes...no. Why?