  While the precise mechanism responsible for the L to T dwarf transition
remains unclear, it is clearly caused by changing cloud characteristics. Here
we briefly review data relevant to understanding the nature of the transition
and argue that changing atmospheric dynamics produce the transition by opening
holes through the global iron and silicate cloud decks. Other possibilities,
such as a sudden vertical collapse in these cloud decks are also considered.
Any acceptable model of the L to T transition must ultimately connect changing
cloud properties to the underlying atmospheric dynamics.
