The problem here is that "galumph" is indeed a word: one that the writer might have been unaware of and used as if it was an onomatopoeic word they had just invented.

When I was a child, we often said we were galumphing, which was when we were pretending to gallop like horses, but couldn't manage anything that elegant (especially when in mud and shod with wellies). Note that "galumph" is actually a bit onomatopoeic for the noise a kid in wellies might make when trying to gallop like a horse.

www.dictionary.com/browse/galumphv. "to prance about in a self-satisfied manner," 1872, coined by Lewis Carroll in "Jabberwocky," apparently by blending gallop and triumph. Related: Galumphing. Slang definitions & phrases for galumph Expand.

https://en.oxforddictionaries.com/definition/galumph'Ou... new Art teacher galumphed into the classroom with all the energy of a tropical hurricane.' 'He or she must jump or leap or, to use a word coined by Lewis Carroll, galumph through the deep snow.'

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Note added at 18 hrs (2016-12-01 15:52:04 GMT)
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www.merriam-webster.com/dictionary/galumphintransitive verb. : to move with a clumsy heavy tread.

https://www.vocabulary.com/dictionary/galumph
To galumph is to move in a heavy, clumsy, ungainly way. Ballerinas are unlikely to galumph.

" One, two! One, two! And through and through
The vorpal blade went snicker-snack!
He left it dead, and with its head
He went galumphing back.

"And, has thou slain the Jabberwock?
Come to my arms, my beamish boy!
O frabjous day! Callooh! Callay!'
He chortled in his joy."