Are Natural Disasters a Sign of God's Judgment?

How are we to interpret natural disasters? Are they necessarily a sign of God's judgement? For the creation was subjected to frustration, not by its own choice, but by the will of the one who subjected it, in hope that the creation itself will be liberated
from its bondage to decay and brought into the glorious freedom of the children of God. http://vref.me/ro8.20-21