Our Beautiful World
In for another adventure - to visit Hraunfossar.
East of the town of Borgarnes, some few miles north of Reykjavik.
(On the map North is to the left, East is up).
The Hraunfossar waterfalls consist of countless springs of clear water that emerge
from under the edge of the lava field Hallmundarhraun and flow into the river Hvítá.
Hallmundarhraun consists of pillow lava and is believed to have been formed in about 800 AD,
shortly before the first recorded settlers arrived in Iceland.
It is named after Hallmundur, who according to Grettis saga lived in the area.
Surface water and melting water from the glaciers runs between the lava layers and emerges
to form the Hraunfossar falls, which are about 1 km wide and splash down into the Hvítá
among the rocks and birch-scrub vegetation all year long.
The waterfall Barnafoss is where the channel of the Hvítá narrows just above Hraunfossar- see next picture.
The average flow-rate is 80 cubicmeter per second, but in flood it has reached up to
500 m³/s; when this happens the river breaks out of the narrow channel
and floods over the sorrounding area.
Here the river has carved out bridges and stone arches and scupted the rocks with its violent force.
The Hallmundarhraun-lava area comes from a volcano east of the Eiriksjökull glacier,
on the NW edge of Langjökull. The lava-field is about 70 km long, and is marked
on the map above by green dots. It stops just 1 km east of Hraunfossar and Barnafoss.
This special lava-field consists of hardened once thin-floating basaltic magma filled with gas.
Most of the latest floating lava ran through tunnels under the surface.
Such lots of caves where formed. That is why you can find the largest cave in the world
right here, the Surtshellir, and also Stefánshellir and Viðgerhellir, which is about 1,460 m long.