I think the angel in a whirlwind directing the storm was a beautiful portrayal of faith. It says that whatever trials and turbulance we may go through, (the storm), has God's hand (the angel) directing the ultimate outcome. That was my thought when President Bush first spoke those words, and it applies even more now.
God does not cause tragedies, but he CAN and DOES direct the outcome.
I recall McCain's moving speech at the convention, "I am haunted by the vision," where he meant an awe of the future potential of the USA. I suppose the eloquent "angel rides in the whirlwind" phrase can be interpreted poetically, but I was looking at it in a exegetical way.