No expert on cricket but I believe that bails can be dispensed with altogether if they are in danger of being dislodged by gusts of wind. Don't know if it's ever happened before.
Just had a word with Uncle Google (Googly's smarter brother) and he says I was correct. He also said that sometimes heavier than normal bails are used to avert the problem. If the bails are dispensed with, Hawkeye assumes they are still in position.
Cricket stumps and bails are usually made of high quality Ash. In windy conditions heavier bails made of a denser wood generally Lignum Vitae can be used. LV is the same wood used to make traditional crown green bowling balls.