Here's a transcript from that part of the podcast:
Nic: Okay, so she's found in, this is a field?
Renner: Yeah, it's a wheat field.
Nic: Okay, in February. So there's not, this isn't tall wheat in February?
Renner: No, it's been harvested. It's cut down. She was dumped there after the harvest, uh, back in...her body had probably been there within 24 hours of when the abduction occurred.
Nic: Is she right by the road? Is she away from...?
Renner: She's up uh, about, she's probably about 25 feet from the road.
Nic: Okay.
Renner: On a little rise. Uh, it's possible that her body had been covered with a canvas tarp, and then covered with snow. And then the snow had just melted early February. And I think that's why the jogger saw her that day.
Does this sound like a possible scenario? If there wasn't any snow until December, could Amy have laid unnoticed in the field, covered only by a cloth tarp for 1-2 months?
I guess the implication is it snowed, the snow melted, and the tarp was then removed or blown away.