From the Icelandic Met Office

It is believed that a small subglacial lava-eruption has begun under the Dyngjujökull glacier. The aviation color code for the Bárðarbunga volcano has been changed from orange to red. Image follows.

Volcanic Eruption
© Icelandic Met Office

Webcam image showing either soil/dust being blown into the air by gas venting or ash being ejected.
Bárðarbunga volcano
© WattsUpWithThat