A jökulhlaup has started in Múlakvísl, the glacial river that comes off Mýrdalsjökull, that is the glacier that Katla is under.

No eruption at this point though.

RUV has a webcam on it (32 bit wmv) – not much to see at midnight EST

Lots of

small earthquakes in a line
across the caldera though.
Some have a depth of less than a km, and are, most likely, just the ice shifting,
but there is steady activity down to 10-15 km depth, suggesting some magma movement.

Police are warning of strong H2S odour on the sands, and possibly lethal concentrations of the gas in low lying areas nearby.

Mýrdalsjökull on 8th July 2011 – the big round thing is Katla’s caldera – the outlet glacier in the foreground (from mbl.is)

Múlakvísl is the outlet river on the western edge of the sands, few km east of Vík, if Katla erupts it will probably go to very high flood stage, and the sands become impassable.

The river is rising, not clear when it will peak at this stage, water conductivity is high, indicative of high concentrations of ionic salts, and geothermal origin.
I used to take samples of the river water, for the hydrology group, using a boom off one of our trucks, hanging off the bridge across the river. Checking on salts and solutes.
Every time I’d swear the damn sulphide smell got stronger, we had instructions to cut the wire and leave fast if the smell spiked and the river started rising.

testing the water in 2001 during a previous rise in sulphides (from mbl.is)

The last proper jökulhlaup in 1955 took the bridge out.

As usual, Jón Frímann is on it

PS: holy crap!
This is a snapshot from the water meter upriver – level jumped 5 meters in minutes, the downriver meter by the bridge jumped 3 meter, then leveled off – probably getting a dam from the bridge floor.


PPS: at 5 am RUV is reporting the bridge across Route 1 at Múlakvísl is overtopped by the flood, and it does not appear to have peaked.
Route 1 is closed at Mýrdalssandur.