Wikipedia
A sunbreak is a natural phenomenon in which sunlight obscured over a relatively large area penetrates the obscuring material in a localized space. The typical example is of sunlight shining through a hole in cloud cover. A sunbreak piercing clouds normally produces a visible shaft of light reflected by atmospheric dust, called a sunbeam. Another form of sunbreak occurs when sunlight passes into an area otherwise shadowed by surrounding large buildings through a gap temporarily aligned with the position of the sun.
The word is considered by some to have origins in Pacific Northwest English.
Usage examples of "sunbreak".
There was only one approach to it—from the Upper Sunbreak side, through a gorge so steep and narrow that a hundred warriors could defend it against a million.
He moved quickly, and as they had rehearsed, he and the explorer slapped the rig together and set up a gleaming plastic skin sunbreak to shield the rocket plane.