An isolated "Water Ice Cloud" over Tharsis or a volcanic "Plume"? (Saturated Natural Colors; credits: NASA/JPL/MSSS)

Original caption:"This composite of red and blue MGS-MOC daily global images acquired on 6 July 2005 shows an isolated water ice cloud extending more than 30 Km (more than 18 miles) above the Martian surface. Clouds such as this are common in late Spring over the terrain located South-West of the Arsia Mons volcano. Arsia Mons is the dark, oval feature near the limb, just to the left of the "T" (in the "Tharsis Montes" label).
The dark, nearly circular feature above the "S" (in "Tharsis") is the Pavonis Mons Volcano and the other dark circular feature, above and to the right of "S" in "Montes," is Ascraeus Mons.
Illumination is from the left/lower left.
Season: Northern Autumn/Southern Spring".

Nota: purtroppo non ci sono vulcanologi nel Gruppo Lunar Explorer, ma la sensazione (nulla di più) che la "isolata nuvola di ghiaccio d'acqua", come la chiama la NASA sia, in realtà, il residuo di un evento vulcanico, è molto intensa (confrontate la sua forma con qualcuna delle "volcanic plumes" di Io...).