Yes, that is a double. Snaefell ist already called the snow mountain, but I bet not everybody here speaks Icelandic (and I do not speak it, just figure it out). Also: Americans tend to speak of the Sahara desert. So these names seem to be ok to some degree.
The flag was placed at the mountain hut up there. We went inside and got great advice. We did not stay the night up there, though. Which would definitely have had fun.