The geomagnetic storm is what happens when the White Frost reaches your world.
It's not just winter, its an Endless Winter. There are clear references to summertime when lakes are swimmable, and empty raised garden beds for growing food in Pleasant Valley - impossible if the region were snowy year-round. Given that some players have reached game-lengths of almost 30 years and conditions have not changed, we have to assume that the White Frost has arrived. The snow is here to stay, and its only going to get colder...
