Fallstreak HoleThe reason a fallstreak hole is sometimes called a “hole punch cloud” doesn’t need much clarification: It looks like someone used a massive hole-puncher on a cloud. Though these droplets are at below-freezing temperatures, the lack of anything solid for them to form ice around keeps them in a liquid state. When the upper cloud layer is warmer than the lower layer, it’s also less dense, and it can move along more quickly than the colder, denser cloud below. Asperitas CloudIn 2008, Cloud Appreciation Society founder Gavin Pretor-Pinney suggested that the World Meteorological Organization add a new designation to its International Cloud Atlas to describe tumultuous, billowing cloud waves that lack an obvious pattern. Though they’re most commonly seen beneath a storm cloud following severe weather, they can also form from fair-weather clouds like cirrus and altocumulus.