I'm sure there are more interpretations of this dream, but what I saw was this....A world lost without Jesus - Who IS THE LIGHT OF THE WORLD. When we do not know Jesus, our souls are as black as black. There was absolutely no light! And this is the darkness to which we are called as Believers to dispel. To carry HIS Light to a lost and dying world.
The above photo is a lighthouse which is still in use at the pier in South Haven, Michigan. Even though we did not capture the light shining, it still sends out it's beacon to travelers on Lake Michigan. The black snow clouds of Michigan's frozen winters are deepened by the contrast of the sun breaking through the clouds to the south....again, not showing in the photo, but still present.