The L to T Dwarf Transition
  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. 
M.S. Marley, M.C. Cushing, and D. Saumon