Snow isn't the issue, really. Snow, sand, light dirt - all have to be sifted. Ash has to be sifted. There are various electronic gadgets that pick up something warm/hot, something metal, something electronic. I think they can even pick up luminescence. Certainly, there are other methods for looking into bodies of water (but the problem would still be uncovering anything interesting or suspicious). Someone upthread said "wood chipper" and the only other thing I can think of is "crematorium."
Anyway, the real problem is that once the signal is picked up (let's say they used some form of ultrasound, expensive and slow, but that's what they did), then you have look under layers of whatever is on top.
They behave as if they're looking for something specific already. Probably not metal.
There aren't too many technologies that can see below the visible surface of things. Disposed phone - yes. "Any solid item," well...you'd need a team of experts to look at all those ultrasounds, and it would take weeks to collect them, I'd think. You'd need a team of forensic anthropologists if you were looking for the smaller bones (or parts of the skull). Bones can look a lot like other things, unless you have x-rays. X-raying that vast an area? Probably not practical and easier to dig if you're only doing a small area.
There are technologies that can use drone footage of various kinds, too, but still of limited use in this context. Most take months to analyze. Repeated passovers, that kind of thing.
So, if they are looking for electronics previously signaled to, say, an electronics dog...the device must be in pieces?
It's driving me nuts too. The idea that the snow plow flipped some piece of clothing over into the side of the road is the best one I've heard so far.
Yeah. Odd. Unless most of it is ash, that seems unnecessary. They'd have to think the body was scattered and perhaps crushed. I guess if they have no idea what condition a body is in, or there's any way it could have been scattered and crushed, it would make sense. I feel as it is some really specific item that someone who wasn't thinking clearly may have left in the area.
I will say that just the right "small object" can absolutely make a case. A DNA-covered murder weapon (or parts of it). Shell casings. Small knife. Something belonging to the victim.