The Icelandic meteorological office website has a section on Aurora forecast, there is a rating scale, ranges from 1 to 9, which indicates the strength of the aurora activity for that day. Throughout our visit, the scale had never risen above 4. But that day, the scale was at 9!!
Naturally we were very excited, but when we got up around midnight, the sky was entirely overcast. Slightly disheartened, I set up my camera and pointed it towards the sky. This was the result of it. The northern light was so strong, it had lit up the clouds for as far as the eye could see!