How does Lucy die in the poem "Lucy Gray" by Willam Wordsworth?

Little Lucy Gray became lost in a snowstorm as she set out while carrying a lantern in order to meet her mother and direct her way home from the town.
Wordsworth's poem about the little girl who became lost in the gray sky and white snow-covered earth is a lyrical ballad comprised of quatrains in sixteen stanzas. The rhyme scheme of abab lends a simple rhythm that allows a tale to be told.
In his poem, William Wordsworth has immortalized the little girl who, under her father's direction, was sent out in the afternoon with a lantern to help her mother find her way home, but a snowstorm came prematurely under gray skies, and the child herself became lost. Now, the poet places her in Nature as a little spirit that lives in an ethereal realm:

That you may see sweet Lucy GrayUpon the lonesome Wild.O'er rough and smooth she trips along,And never looks behind;And sings a solitary songThat whistles in the wind.

Indeed, there is an eternal quality given to Lucy as her song is carried in the wind and, like a spirit, she is sighted on the Moors. There is also a poignant tone to this poem as Lucy's traumatic experience is recounted.