The closest answer we could find that actually had merit to explaining the streak of light in the sky last night was from Jonathan McDowell, An astronomer at the Harvard-Smithsonian Center for Astrophysics:

He said, “It’s from a Chinese rocket, called the Chang Zheng 7 rocket that launched on June 25.  Observation reports from Utah indicate the second stage from the first Chang Zheng 7 rocket, launched Jun 25, reentered at 0440 UTC. ”

Jonathan McDowell said he had “looked for objects near reentry” and had calculated ground track versus time, and saw that the Chang Zheng 7 was over Utah at the time. The rocket stage reentering over the western US tonight was from the first launch of the CZ-7, one of China’s new generation of rockets.

McDowell’s theory is that it’s debris from the new generation of Chinese rockets.
China had launched the rocket, also known as the Long March 7, last month to deliver a prototype shuttle into space.  It’s developers had touted the rocket as “more environmentally friendly,” producing less pollution than previous models.
Jonathan also added, “So far in 2016 there have been 25 reentries of objects massing 1 ton or more. But objects of 5 ton+ class like this are rare.”
There were reports from viewers in Lake County, CA. that they observed the fire debris hit the ground and ignite a grass fire.  Fire crews checked the reported areas and found no fire.  So where did that “hunk of junk” really land?  Our inquiring minds would like to know.
Video credit to Isaac and Angel Garcia
photo credit to Marquee Rotondo