Natural phenomenon
observable event which is not human-made
ridge lift
accretion
Ice egg
Sort sol
bank erosion
extraterrestrial vortex
whirlpool
watermelon snow
1561 celestial phenomenon over Nuremberg
red sky at morning
haze
Mobile Bay jubilee
orbital forcing
tidal bore
seismic gap
Rain shadow
astronomical phenomenon
blood rain
moulin
rain
erosion
natural disaster
cloud
beat
beat
thunder
desert bloom