01-15	river in path
16-20	waterfall at path
21-28	lake or pond
29-49	small animal
50-62	swarm or flock
63-64	cliff drop/face blocks path
65-82	light storm (d100 hours)
83-92	heavy storm (d40 hours)
93-95	fog (d20 yard visibility)
96-00	extra hot/cold (d6 days)