Usually, when there is a strong storm, light thatched or tin roofs blow away, because

During strong storms, light thatched or tin roofs often blow away due to a combination of factors ; option [C]. The high velocity air flowing over the roof creates pressure on the roof surface, while the pressure below the roof remains normal, causing an imbalance that can lead to uplift. [B] Additionally, if the roofs are not tied tightly or securely anchored, they are more prone to being lifted by the strong winds. [A] The complexity of the roof shape can exacerbate this vulnerability by providing more surface area for the wind to catch onto. [D] However, it is not accurate to say that thatched roofs automatically blow away in strong winds; their susceptibility depends on various factors such as the quality of construction and the intensity of the storm.