Fear The Walking Dead has just made killing zombies way harder. In season 7, what has become common practice for the survivors could now lead to their impending demise. The nuclear apocalypse that plagues Texas is a major contributor to that.
Following the dropping of nuclear warheads in the season 6 finale, "The Beginning," the state of Texas has become a radioactive wasteland. In season 7's "Six Hours," Morgan and Grace go out in search of food for baby Mo and to find a place away from the nuclear fallout. During their journey, they encounter two survivors, Fred and Bea, who have been physically affected by the fallout. From Fred and Bea, Morgan and Grace learn how dire things have truly become on account of the nuclear blast. In addition to their injuries, Fred and Bea reveal that, due to a storm, some of the fallout trickled into Louisiana. Therefore, Teddy's nuclear bomb has affected a far larger area than previously imagined. Additionally, there are now zombies carrying radiation on their skin, making any survivor who comes across them susceptible to contact with the radiation.
With that in mind, killing zombies has become harder in Fear The Walking Dead because a hit to the head could lead to the survivor being exposed to radiation. The nuclear apocalypse has already been challenging enough as is with the radiation affecting the area. The addition of zombies carrying fallout on their bodies makes the situation even more dangerous for the survivors.
During the time jump between Fear The Walking Dead seasons 6 and 7, the state of Texas has changed and survivors have had to adapt. In season 7's "The Beacon," viewers see a new group called the Stalkers taking clothes off of zombies. During "The Beacon," it is not specified why the Stalkers were doing this. With "Six Hours," however, viewers now have a likely answer to that question. This is that they are looking for clothing to add extra layers of protection against the radioactive zombies. As shown in the episode, Morgan and Grace kill the zombies by shooting them. In Morgan's case, he has to resort to hitting them with the end of his gun. Any close-range attacks could've put Morgan and Grace at risk of being exposed to radiation, even with their protective suits.
The radioactive zombies in Fear The Walking Dead season 7 pose a huge threat to the survivors. On top of their ferocious nature, a blow to the head now has the potential to deal the same damage to the survivors as a bite would. This raises the already high stakes for Morgan and the others, leaving viewers to eagerly anticipate how they will combat this new danger.