After four years, the Icelandic band will return with Valtari, an album they describe as the sound of 'an avalanche in slow motion'

Sigur Rós have announced details of their sixth studio album, after a four-year hiatus from studio work. The "electronic" album is called Valtari, the Icelandic word for steamroller.

"In one word, it's beautiful," bassist Georg Holm said. "I'd compare [it] to looking at an old landscape painting."

It has been slow going for this follow-up to 2008's Með Suð í Eyrum Við Spilum Endalaust. As previously reported, the band binned their initial recordings. "Session after session went pear-shaped," Holm said in a press release. "We lost focus and almost gave up … Did give up for a while." Sigur Rós eventually took a long break, interrupted by frontman Jónsi Birgisson's solo releases and last year's concert film and accompanying soundtrack, Inni. "But then something happened," Holm wrote, "and form started to emerge, and now I can honestly say that it's the only Sigur Rós record I have listened to for pleasure in my own house after we've finished it."

Despite their long holiday, the Icelanders' musical style seems relatively unchanged. Like previous records, Valtari is described as "dreamy", "floaty and minimal". Nevertheless, "it's not like anything else we've ever done," Holm said. "There's more electronic stuff than before. But don't worry, we haven't made a dance record."

The band released their lead single, Ekki Múkk on 26 March. Birgisson has compared Valtari to "an avalanche in slow motion" and certainly the avalanche sounds very, very slow. A far cry from Takk's bombastic pop, Ekki Múkk is seven minutes of loudening voice, darting strings and vinyl crackle.

Sigur Rós will headline this year's Bestival alongside New Order, the xx and Stevie Wonder.