This article from Bad Astronomer contains a video showing a simulation of a tumbling booster jetting something from two different openings. It looks almost identical to the thing in the sky.
It’s almost certainly a Russian rocket that failed, even though they are denying it. Well, that or the arrival of Azathoth, one or the other.
There are now dozens of pictures of the phenomenon - see my post prior to this - and while the initial assessment you gave may have had some credence as an explanation (though I’ve never seen a beam of light form a spiral before) after the first couple of pictures and videos, it doesn’t stack up either to the distance at which this thing was seen, nor the translucent blue cloud that was visible as the sun came up, nor the exhaust trails at the horizon. And indeed it does seem that the explanation is that it was a rocket failure. Please compare the many pictures of the event now available with the NASA rocket exhaust pictures that Squink posted - as well as the video on the bad astronomer site.
Yes, depending on how far north you are, and how close it is to solstice. So it’s actually correct that it’s the rising sun illuminating the clouds, it just wasn’t going to rise above the horizon.
I was initially curious about the statements saying the blue beam of light shot out of the centre. If it was a beam of light, it would be impossible to determine whether it was shooting out of, or into the centre, because light travels so fast.
However, if (as seems likely) the blue streak is the ascending trail, illuminated by the almost-rising sun, the illumination would progress from top to bottom, exactly as described.