It seems that an small eruption took place in Katla volcano caldera during the night. At the moment it seems to be over. But it is hard to be sure. According to Icelandic news there where three newly formed cauldrons in the Mýrdalsjökull glacier. The eruption is unlikely to break the glacier at current time if it remains small. Newest news reports say that cracks have formed in the glacier around the cauldrons.
Evacuations are currently taking place in Álftaver, Þakgil and any other place that might be danger. People how are close to affected rivers from Mýrdalsjökull are urged to get away from them due to danger of dangerous gases in the glacier water.
The bridge over Múlakvísl is gone, it did vanish the flood water early this morning. According to the news the bridge got flooded around 03:00 UTC last night. This means that Road 1 is closed in this area.
Currently earthquake activity continues in Katla volcano caldera. But the tremor has been dropping for the past few hours after it topped around 03:00 UTC last night.
The tremor has dropped, but is not down to background levels yet. This might be small eruption for the moment. But I fear that might change in the next hours to few days. There is also an big risk of new floods from Mýrdalsjökull glacier due to this small eruption, or if new fissures open up at new places.
I am going to post more updates when I know more. At the moment, this is just an small eruption. But as told before. That might change without any warning at all.
News in English.
Possible eruption in Katla (Rúv.is)
News in Icelandic.