It's actually flying dirt, bits of pieces of tiny meteors hitting the Earth's atmosphere. They are traveling at high speed and leave little streak as they burn up on entering the atmosphere.
It's the Perseid Meteor Showers. With scant moonlight at this time of the month, the darkened skies provided a canvas for people living in Washington state to view the meteor shower. It peaked overnight Sunday into Monday.
The Perseids should also be visible Monday night, although you won't see as many of the shooting star type variety that was evident overnight on Sunday wiht the naked eye.
The metors appear anywhere in the night sky. For best viewing, get away from city lights and be prepared to wait a while.
Why are they called perseids? They may appea rin different parts of the sky, but they actually all originate from one point in the sky. That's called the radiant. The radiant point is the constellation Perseus.