And also, what is that sign? I saw it from the northern windmill (photo).
It's just an easter egg, don't pay attention.
Deer may be displayed on the radar, so you shouldn't panic too much from every dot either.
As for the rest, it's hard to understand what could have caused the explosion. But there are a couple of loud events that can turn everything upside down at the base. One event happens according to the story on a certain day (I won't say when exactly, I don't know). And the second happens when you catch a certain signal and is accompanied by a blue light and a rumble. Both events eventually leave stationary dots on the radar and you can go there.