Great day to find out.

My area got hit with the ice snow overnight and it's still going. When I try to put my jeep into 4 wheel drive (2015 trailhawk) it's saying drive mode unavailable and the dial flashes to the snow setting then goes back to auto. I've tried in park and drive, with and without traction control. Hopefully I'm just dumb and not doing something correct. I haven't really used 4wd, but the settings seemed to work. Any suggestions?