Interesting times on 6m tonight. I spent a pleasant hour bouncing signals off the Aurora. There were many stations calling from all over the US and this was the first time I have ever heard the Aurora Flutter.
Aurora Flutter normally occurs when radio signals are reflected from the auroral curtain. SSB signals that are reflected sound very raspy, sound like the other operator is talking in a quiet whisper, and are difficult to understand and tune in.
At 2300 UTC the A Index was at 100 and the K Index was 7. I have never seen the A Index that high before.