Tracks.. from the sky?!

The tracks of a bipedal creature were laid here within the hour, leading
from up to south. The tracks of a bipedal creature were laid here within a
half-day, leading from up to north.

Exits: north east south west

Apparently if you leave a tent and go some direction, you come from the "up" exit descriptor.

Typically, this is when admins bring big groups down in to the game - leaves an "up" track.