Undular bore

In meteorology, an undular bore is a wave disturbance in the Earth's atmosphere and can be seen through unique cloud formations.

They normally occur within an area of the atmosphere which is stable in the low levels after an outflow boundary or a cold front moves through.

However, because of gravity, the water or medium is pulled back down and the repetition of this cycle creates the transverse wave motion.

Rare but not unknown in a great many locations, the waves appear with some predictability and regularity in the Gulf of Carpentaria during spring.

They have been seen as frequently as six days in a row according to reports by the two pilots who have most experience with soaring these sometimes enormous examples of the undular bore, known in Australia as the Morning Glory cloud.