Laura Veirs, The Spitz, London

A geologist-turned-musician, the Seattle-based singer-songwriter Laura Veirs discovered her vocation in circumstances that must be unique, even among the denizens of the one-time grunge capital. It was a decade ago, while she was on a student field trip in the Taklamakan desert of north-west China, that the bespectacled 30-year-old began plotting her future on a cheap guitar.

In the years since, while variously eking out a living as a teacher, maths tutor, science demonstrator and gardener, Veirs has released four albums. In her songs she's melded ancient folk, blues and old-time ballads with a decisively modern approach, displaying a feel for the great outdoors, the changing seasons and the elements perfectly in keeping with an art that first sparked to life in a distant desert.

This year she released Carbon Glacier, a masterpiece of tremulous contemplation, wonder and creative tension. On the album Veirs uses the vast Pacific northwest from the Rocky Mountains to the icy Pacific Ocean as a backdrop for personal fears, longings and memories. It's a vast landscape open to many, but accessible perhaps only to those with a certain sensibility. Veirs is evidently just the gal. She and her electric guitarist Karl Blau arrived in London for tonight's show after a delay in a Swedish airport set in the middle of a forest, where she passed the time "imagining forest cats hiding behind trees in the shadows".

"Lost at Seaflower Cove", in which she sings of "sea shanties that shatter and chatter" and "tattooed sailor men" evokes her landscape. On "Rapture" her voice shivers with naked candour, but there's a steely inner strength as she ponders such troubled souls as Virginia Woolf and Kurt Cobain.

Tonight Blau is the only representative of The Tortured Souls, the band whose off-kilter arrangements make Carbon Glacier a minimalist joy, and backing tapes don't do justice to the album's foreboding atmosphere. But Veirs's vocals surpass expectations. Spare and resolute, they present her as a witness, determined to capture the immensity and strangeness of humanity and nature.

Whether finding the airborne groove of "Cloud Room", the lovely yearning and ache of "Raven Marching Band" or the spectral visions of "Ether Sings", she brings real emotional impact to her angular, earthy poetry. Gazing at a remote point, she's an unassuming, studious presence. But Veirs's ability to chart a course beyond the workaday pop-rock hinterland, as in the set closer "Riptide", comes from personal application and experience.

A winning contrast was offered by the the wry, rollicking encore "Black-eyed Susan", where she and Blau evoked their honky-tonk roots. A warm glow was cast over the magnificent, cold, dark terrain they'd left in their wake.