Question

Why roofs get blown off during a storm????????????????????????????

Answer 1

because when the speed of the wind increases its pressure falls. So the the pressure above the roof is lower than its pressure below ..........This creats up thrust and roofs get blown off.................................

Answer 2

its due to Bernoulli's principle.... 
its because due to the high vel wind blowing over the roof ,the pressure below the roof is greater than above the roof , the roof get lifted