Selfoss

Selfoss is located a kilometer upstream of Dettifoss and is accessed from the same locations as Dettifoss. There are two roads which access the falls, one on either side of the suspension bridge along Highway 1 which spans the Jökulsá á Fjöllum, which itself is found 130km west of Egilsstaðir, or 35km east of Reykjahið (Myvatn). Both roads are signed for Dettifoss. To reach the east side (easier access) of the falls, take Route 864 - which branches from Highway 1 just east of the bridge - north from Highway 1 for 32km, then turn left where a sign points to Dettifoss, the parking area will be found another 0.75km down the road. A trail then leads about one-third of a kilometer down to the first viewpoint of Dettifoss. Watch for a wooden sign pointing out the trail heading upstream to Selfoss, which will be encountered in another 1.2km of relatively easy (though somewhat rocky and sometimes muddy) walking. Note that Route 864 is gravel and as of August 2014 was in pretty rough condition (2wd vehicles are allowed on this road, it just needs to be driven slowly). To reach the west side of the falls, take Route 862 - which branches from Highway 1 about 9.5km west of the bridge - north from Highway 1 for 22km - then turn right where a sign points to Dettifoss, the parking area will be found just over 3km further. A trail then leads down to the rim of the gorge opposite Dettifoss in another kilometer. Selfoss will be another kilometer upstream from this point. Note that Route 862 was formerly classified as an F-Road (4wd high clearance only), but that does not appear to be the case any longer.Selfoss is the first waterfall in the Jökulsá á Fjöllum (River) as it begins its descent down the massive Jokulsargljufur. At the falls the river transitions from a broad, desolate volcanic plain to a rugged canyon carved in expansive columnar basalt. The river has carved a narrow notch in the basalt formations to form a long, narrow horseshoe shaped canyon where it plunges 44-feet in a furious roar. Because of the large volume of water involved, the river pours across a huge expanse of the bedrock, causing the crest of the falls to stretch to well over 1,200 feet in length - likely making Selfoss the widest waterfall in Iceland (or if not then certainly among the top 5). Though the Jökulsá á Fjöllum is (apparently) on average only the third largest river by volume in Iceland, because of the width of the falls, Selfoss ranks among the most powerful waterfalls in Iceland and certainly can be compared favorably to many of the larger waterfalls in mainland Europe as well - though it is nowhere close to as powerful as Dettifoss, found just downstream. Signs at the parking area indicate that the river's discharge averages about 14,125 cubic feet per second in the summer months, but this contradicts the river gauge measurements we've been able to find which shows the flow to vary from about 3700 cubic feet per second in the colder months to about 9,500 cubic feet per second in the warmest months of the summer, with peak flow hitting over 20,000 cfs periodically. In addition to the wildly varying volume of the river, the Jökulsá á Fjöllum has been prone to several immense Jokulhaups, or Glacial Outburst Floods, in the past. Often these floods have been instigated by volcanic activity in the Barðarbunga caldera, which lies beneath the glacier that sources the river. The Jokulsargljufur was likely formed by several such floods repeatedly scouring the bedrock. Some analysis suggests that in order to account for boulders which have been deposited in certain locations throughout the canyon that the volume of water involved in such floods would have had to have been greater than the volume of the Amazon River! Obviously such an event would be short lived however. This hypothesis has achieved recent attention due to the recent volcanic activity at Holuhraun - which in fact began the day we arrived in Iceland, and two days after we visited Dettifoss and Selfoss the roads accessing the falls were closed off in precaution (the volcano didn't begin erupting until after we had left the country). Thus far there has been no indication of an imminent flood, however should one occur as a result of the activity, there is potential for the canyon to be permanently altered.