The aviation colour Code for Katla has been changed from green to yellow, meaning that the volcano is experiencing signs of elevated unrest above known background levels.
Icelandic authorities have also started contingency plans in case of an eruption. Katla is now long overdue a full-blown eruption, the last being in 1918. Seismic activity has been ongoing since the end of August and the authorities are now taking the necessary steps to prepare for what may come.
Katla Volcano: Civil Protection Uncertainty Phase Declared | Iceland Review