© Glenn RogersWeird cloud formation, Perth Australia
Anyone fearing an alien invasion can now have their minds put at rest as experts at the Bureau of Meteorology have confirmed their original suspicions are true - the strange phenomenon sighted in Perth skies this morning was in fact a Fallstreak Cloud.
According to the bureau's Neil Bennett, the cloud - which was sitting high above Perth Airport - contained extremely cold water particles.
© Daniel James Hall
The newly frozen ice crystals inside the cloud became a lot heavier then the cloud itself.As a result, the heavier ice crystals fell through the cloud, leaving an usual hole - just like the one Perth locals reported seeing this morning. A Fallstreak hole is a cloud formation that gives the appearance of strange holes in the sky's cloud layer.
The unusual sight is causing quite a storm on Twitter with many locals continuing to speculate that the cloud may be evidence of something a lot more sinister.
Mr Bennett said: "It doesn't occur often so it's no surprise that it's causing quite a stir".
Surely jet exhaust is hot and water freezes at zero degrees (dependent on pressure)
I assume by Extremely Cold they mean something already below freezing
e.g. Contrails
Jets leave white trails, or contrails, in their wakes for the same reason you can sometimes see your breath. The hot, humid exhaust from jet engines mixes with the atmosphere, which at high altitude is of much lower vapor pressure and temperature than the exhaust gas