Six years after Aerial’s bursts of summer sound, Kate Bush’s winter album arrives, each track exploring the long Christmas months. They reflect a season which brings out the profound and absurd in equal measure – the feelings of longing and loneliness that emerge as the dark nights bed in, the party-hat silliness that pops up when the same nights stretch out. 50 Words for Snow initially aims for the former value, with Bush’s son Bertie taking the opening vocal on Snowflake. "I was born in a cloud," he sings eerily, like the ghost of Little Lord Fauntleroy; he is constantly falling, all "ice and dust and light". His mother keeps appearing – he sees her "long white neck" – promising to find him, but we don’t find out if she does. On paper, it’s a lovely concept. On record, it treads an exceedingly fine line between the sublime and the ridiculous.

But this is classic Kate. On 1993’s The Red Shoes, Prince had to play second fiddle to Lenny Henry on Why Should I Love You?; on Aerial, Rolf Harris performed on two songs. But Bush has always been almost wilfully uncool, and this time around is no different. Take Stephen Fry taking the lead on the title-track, whispering fifty synonyms for the white stuff, from the lovely "blown from polar fur" to the frankly daft "phlegm de neige". It sounds embarrassingly cold, perhaps because of his ubiquity – if only Vincent Price was still alive, or Ian McKellen was available. Another guest, Elton John, fares much better on Snowed in at Wheeler Street, partly because his voice takes on a gentler quality than usual, partly because the song maps the movements of lost love very beautifully, and partly because John was Bush’s first hero; you can hear this depth of feeling as their voices mesh together.

The album only really reaches the heights Bush has set for herself when she appears centre stage. Her voice is noticeably older now, full of earth, heft and husk, and works stunningly well with little more than her piano’s sustain pedal – especially in Misty, her already widely-commented-upon love song for a snowman. Giving Raymond Briggs’ famous concept an X-rated twist – he is "melting in my hand", the next morning "the sheets are soaking" – its 13 minutes are spellbinding. The album’s finale, Among Angels, is even better, a torch-song for a friend in need, with a stunning central lyric: "I can see angels standing around you / They shimmer like mirrors in summer / But you don’t know it." Throughout, the piano sets a magical mood, all dark, loud and heavy.

Just after the song’s start, you also hear Bush stop for a second, take her fingers off the keys, and whisper the word "fine". In Lake Tahoe, the song also breaks suddenly at 8.44, leaving Bush to exhale one sharp, startling breath. 50 Words for Snow may threaten to lose its way in the blizzard sometimes, but it is moments like these – jolting us from her world for a moment, reminding us of how all-embracing her talent can be – that show just how much she can move us with her fire and ice.