In keeping with stratocumulus and altocumulus in the lower levels, cirrus clouds in the high etage (over 20,000 feet) have a cumuliform species – cirrocumulus. As with the other two, cirrocumulus is formed by convective processes, the vertical development giving the individual cloudlets their heaped appearance. When arranged properly, cirrocumulus takes on the appearance of fish scales, making it the “mackerel scales” in the “Mares’ tails and mackerel scales . . .” proverb. Another arrangement gives the appearance of ripples in the sand.It’s often difficult to distinguish between cirrocumulus and altocumulus, with the same cloud formation sometimes being both simultaneously. The only thing setting them apart might be that part of the formation is below 20,000 feet, while the rest is above. Cirrocumulus might contain some super-cooled water droplets, but they’re not very long-lived, soon turning to ice crystals. Cirrocumulus is usually a transition phase between cirrus (mares’ tails) and cirrostratus, as the cloud thickens and the weather system moves in. Cirrocumulus might produce some precipitation, but only in the form of virga, which never reaches the ground. It can be an indicator, though, of precipitation to come, as the clouds thicken and lower.