Virga (aka fallstreak, fall-stripe) are generally streaks of rain or snow appearing to hang under a cloud or tapering down from the cloud base, descending and evaporating before reaching the ground. The name of this supplementary cloud feature derives from the Latin virga meaning 'rod' or 'stripe'. Virga (vir) are especially good to observe during sunrise or sunset when the back-lighting from the sun illuminates the reddish stringy trails.
Virga are accessory clouds associated with cumulus, cumulonimbus, altocumulus, stratocumulus, cirrocumulus, nimbostratus, and altostratus. However, they may not be confused with the supplementary cloud feature praecipitatio - visible rain, drizzle, snow, hail or ice pellets actually reaching the ground.
Cirrus cloud are often both associated to and mistaken for virga. Tufted cirrus clouds with virga are populary named mares' tails. Particulary cirrus uncinus (hook-shaped cirrus) may be regarded as virga, but are normally not recorded as such.