Re: cold weather front....
Vic, dirt holes sets are pretty much all I use. That particular location was set up for coyotes.....650 traps, trap back about 9" from the hole, coyote gland lure. Because it is so far out in the open, I would be surprised to catch a fox there. It is a large drainage ditch running under a farm lane. It has produced 7 coyotes and no fox since last season. Coyotes run the terrain features like the ditch and the lane, so when you get an intersection, it's a good place to set. The other pic is a brushy ditch intersecting the same farm lane about a half mile away. Fox like the cover. Same time period, 10 fox and 4 coyotes. The traps are closer to the hole, and a mix of 550s, 450s and bridger #2s. I have better luck on fox with pan tension under 2#.