Vicente Amigo and others, Celtic Connections, Glasgow

Unfrozen pipes at the best festival of the winter

Malian singer Salif Keita performs on July 30, 2011 in Abidjan during a concert for national reconciliation following post elections violence. He will perform at Celtic Connections in February (Getty Images)

Celtic Connections - the Glagow music festival that might be loosely described as a winter Womad - is now in its 20th year, and its lighting-up of dark days and cold nights remains a unique and enthralling enterprise.

This year's Celtic Connections spans 17 days, runs to some 250 shows, and features around 2,000 musicians. The relatively narrow focus that might once have characterised the festival is very much a thing of the past, and "Celtic" in this context is less about geography and culture and more a state of mind.

Those concerned that the original concept might be dissipated by the inclusion of acts as diverse as Malian legend Salif Keita, the choral wonders that are Le Mystere des Voix Bulgares, and the peerless Latin-flavoured country rock of The Mavericks - to name just three from the 2013 line-up - have no grounds. If a stunning opening weekend showed anything, it was that at Celtic Connections you are never far from a pipe and fiddle.

Even within traditional forms, musicians of the calibre that Celtic Connections draws can create entire worlds of feeling, none more so than two Spanish giants who played the Royal Concert Hall on Friday and Saturday respectively - Flamenco guitarist Vicente Amigo and Galician pipe-player Carlos Nunez.

Amigo was world-premiering his Flamenco\Celtic project "Tierra", and if there were times when he and his band produced the kind of slightly lush, sentimental sounds that no tourist board would have objected to, that could not detract from the artistry on offer. Nunez's pipe-playing - supported by the Royal Scottish National Orchestra - was a revelation, his generosity of spirit totally at one with the Celtic Connections ethic.

The smaller venues offered no less arresting experiences. The green room at the Concert Hall on Friday late-night showcased dazzling Canadian rockabilly outfit Petunia and the Vipers who so completely inhabited the genre as to go way beyond pastiche. (This show went out live on Radio 3 and is well worth i-Playering).

The crypt at Oran Mor thrilled to the surging guitars of Glasgow indie outfit Washington Irving. The Luke Daniels band, in an upstairs room at Walkabout, was all jousting accordions and foot-tapping ebullience, and Ethiopian jazzman Mulatu Astatke brought his mixture of cool abstractions and blistering funk to the splendour that is the Old Fruitmarket. I also loved the pipe-playing of Highlander Callum Stewart, who turned up in a couple of places.

But for me nothing went deeper than the Sunday night at the Concert Hall dedicated to late great member of The Band Levon Helm that featured his daughter Amy, Beth Orton, and some 25 others, climaxing unforgettably in mass renditions of "The Night They Drove Old Dixie Down" and "The Weight". This "Roaming Roots Review" was was deftly curated and overseen by Roddy Hart, and of the many talents on display the stand-out for me was Wisconsin singer Cory Chisel, whose voice - early-70s Dylan and then some - pinned you to the wall. Celtic Connections is on till 3 February. Get there if you can.

@SimonOHagan