abstract
atmosphere
background
chamonix
clouds
clumps
disturbance
formation
gathering
gray
horizontal
imminent
impending
instability
lobes
mammatocumulus
mammatus
meteorology
midwest
mont blancm
northern
obliterate
obscure
ominous
opaque
paraglider
phenomenon
sky
skygliding
spring
storm
system
threatening
thunderstorm
unstable
weather