Altocumulus castellanus cloud
（重定向自Altocumulus Castellanus）
![](/Images/godic/202412/20/Altocumulus-Castellanus1916.jpg")
![](/Images/godic/202412/20/Altocumulus_castellanus_break_21916.JPG")
![](/Images/godic/202412/20/Castellanus-Corfidi1916.jpg")
![](/Images/godic/202412/20/SkewT_Norma_2006.07.13-12-001916.jpg")
Altocumulus Castellanus (ACCAS) is named for its tower-like projections that billow upwards from the base of the cloud. The base of the cloud can form as low as 2,000 metres (6,500 feet), or as high as 6,000 metres (20,000 feet). They are very similar to cumulus congestus clouds, but at a higher level.