Hannah Conwald's Mother-in-Laws

The key here is the older woman with the letter. We assume she's a mother-in-law of Michael, who we see kill himself in the beginning of the show. One of the ways that they establish familiar relationships in this episode is through the family photo. It just adds to the general creepy malaise that seems to hang over a wind and, yeah, to see the two huge reactor thingies only increases that sense of danger.