Only a few orchestras around the world have programmed a complete cycle of Sibelius symphonies this year to mark the 150th anniversary of the composer's birth. The Berlin Philharmonic just completed its traversal under Sir Simon Rattle last month (in Berlin and London), and the Seattle Symphony – the only orchestra in the U.S. to undertake all seven symphonies in back-to-back programming for the jubilee year – embarked on its Sibelian marathon Thursday evening.

The Festival got an added last-minute jolt from the recent announcement that Thomas Dausgaard, in his inaugural year as the SSO's Principal Guest Conductor, will take over the reins of the BBC Scottish Symphony Orchestra from Donald Runnicles starting in September 2016. Meanwhile, there was a bit of introductory ceremony before the music started on opening night: Finnish Ambassador Ritva Koukku-Ronde was on hand to salute the SSO, whilst the California-Based Finlandia Foundation conferred a new award on the orchestra.

The Sibelius Festival has been named Luminous Landscapes, and there's been a lot attention thus far devoted to the nature factor: the composer's rootedness in the Northern landscape (even to the point of drawing comparisons between Finnish scenery and that of the Pacific Northwest). Of course if you try to sell Sibelius with too many images of pristine lakes and wind-blasted winters, there's a danger of turning a prolonged encounter with his work into a series of sonic Instagrams or musical eco-tourist stops – the contemporary equivalent of Romantic programme music.

Yet Dausgaard showed that his agenda thankfully has zero tolerance for 'easy listening'. The brass snarls beginning Finlandia sounded the opening salvo of an approach determined to give voice to the full spectrum of Sibelian affects, including his capacity to shock and terrify. Dausgaard underscored moments of surging momentum, and he seemed to signal a particular interest in tracing the stations of Sibelius' evolution throughout the arc of the three concerts: thus there was no embarrassment in the bombastic scoring of the middle section, only the fiery ardour of youthful inspiration.

All of this worked to especially laudable effect in the First Symphony. Completed in 1899, this first of the numbered symphonies already benefits from the technique and language Sibelius acquired whilst composing the Kalevala-inspired symphonic canvases of Kullervo and the Lemminkäinen Suite. Rather than a lengthy bit of preludial atmosphere, clarinetist Ben Lulich's opening solo beguiled with emotional complexity, seeming to pose and reflect upon an enigma that will be exhaustively explored – yet left tantalisingly unresolved by the soft pizzicatto chords that end the work.

Here and throughout the program, the players responded keenly to Dausgaard's deeply engaged conducting (he led without score). You get the sense that his rehearsals are exceptionally tightly focused. There was even a hint at moments of slightly too much control at the expense of a little more spontaneity of phrasing, but the conductor had clearly persuaded the players of his vision. One unmissable signature is a fondness for the theatricality of Sibelius' sudden juxtapositions. In the "Quasi una fantasia" finale of the First, Dausgaard pointed up contrasts but kept them from sounding like non-sequiturs. He also accentuated the rhythmic drive of the music, whether in larger architectonic sections or in the rambunctious seven-note Scherzo theme pounded out by the timpani (played by the aptly named Matt Drumm). The tools of the Finnish composer's language became as readily readable as the brushstrokes on a canvas... and all without the aid of dancing polar bears or cavorting reindeer to help us 'get' it. The result argued for the innovative aspects of the composer's use of Romantic rhetoric at this stage in his career.

An expert in Scandinavian composers, the Danish conductor gives the impression of rethinking iconic scores like the Sibelius Second instead of starting with a comfortable cache of received ideas. Here he drew much from high-relief contrasts of dynamics and tempo, particularly in the Andante and Scherzo. The latter made Sibelius sound like a Finnish Haydn of all things, with a host of trickster 'surprises' to shake the complacent listener. Dausgaard can be reminiscent of  Solti in his ability to massage the 'thrill' of a musical moment. Pealing with glorious bright sound, the brass was on exceptional form, undergirded by Christopher Olka on tuba. The Second's final apotheosis elicited a sense of breakthrough all the more satisfying in the context of that tragically enigmatic ending in the First. The effect, in Dausgaard's own commentary, is 'as if the sun is shining on two sides'.