Drought damage becomes a problem when there has been insufficient rainfall or when the soil cannot hold enough water. Drought is typically associated with other factors, such as low humidity and wind, or hot weather conditions. During so, the plant will continue to lose water from its pores, but won't be able to replace it within enough time; resulting in wilting.
In reverse, another type of drought affects the plant slightly differently. Physiological drought involves hot, dry winds which damage the plant above ground. Frost can also cause the same problems; where both scenarios prevent the plant from taking up sufficient water quickly enough.