[Publius]

It woke me up. Not the light. The sound.

I thought it might be the first sign of an earthquake, and I waited for the shaking to begin, but nothing else happened. (I didn't wake up quickly enough to see the light.)

[irishtenor]

I slept right through it. That wouldn't surprise anyone who knows me, of course. I sleep though anything.

[Steve_Seattle]

"It woke me up. Not the light. The sound."

Same here. There was also a shudder, as if someone had slammed the garage door. I looked out my front window (southern exposure - towards Seattle) but only saw the [full or almost-full] moon. In the morning, I found out my son and daughter also heard it.