I wasn't aware God is destroying cities. We have always had weather. Long before there were cities here the Indian's Teepees were blown away by such storms.
But if God is directly responsible for the storms and terrorism (maybe the first but I doubt the latter except in the permissive sense) then His goal may be to show others how much we care by the help we provide for those in need. And to show us the blessings which accompany such help for the needy.
Our church family sent several trucks north to the Houston area with supplies, and several shallow water boats to help rescue those who were stranded in the flooding. (One of our deacons owns a local boat company and he made his inventory available to be taken north for rescue work).
Our church family has donated tons of food and trucks to haul it to those in need.
What a blessing to see God's people putting their faith to work helping others.