The term blood moon really isn't an astronomical term; it was seized on by a religious figure who believes the current grouping of 4 lunar eclipses over the next two years confirms a biblical prophesy. This occurrence, called a Tetrad, really isn't unusual. We have already had several this century, and will have several more.
It refers to the lunar eclipse which will span Monday night into Tuesday morning, and it will be visible in Seattle (weather permitting!). Partial eclipse begins at 10:58, with totality occurring after midnight. The 'red' or 'orange' coloration is the result of the moonlight being scattered by particulate matter in the earth's atmosphere. That, by the way, happens every lunar eclipse, though the exact shade can vary.