Turbines, or whirly birds, are not currently constructed to meet new hurricane codes. The manufacturer recommends removing the top and placing a cap placed over the base in the event a storm is approaching. Additionally, in a high wind, driven rain situation water enters the vent through the vent’s “gills”. We have found bearings to be a normal maintenance item as they wear out and the vent ceases to work properly. We recommend replacing this type of vent.