It was announced today (24-November-2021) that Grímsvötn lake in Grímsfjall volcano is about to start. It is going to take the glacier flood few hours to days to get to the glacier rivers that flow south of Vatnajökull glacier.
This also risks an eruption starting in Grímsfjall volcano. If that actually happens remains to be seen. Last glacier flood in Grímsvötn lake was in 2018, but that did not result in a eruption.