GR translation: He hangs at the bottom of his blood’s avalanche

[Mike Jing]

P25.17-25   Before they took her off she brought his hand over to kiss
anyway, her mouth and cheek in the flare lamps cold as frost, the city
around them at once a big desolate icebox, stale-smelling and no
surprises inside ever again. At which point she smiled, very faintly,
and he knew that’s what he’d been waiting for, wow, a Shirley Temple
smile, as if this exactly canceled all
they’d found her down in the middle of. What a damn fool thing. He
hangs at the bottom of his blood’s avalanche, 300 years of western
swamp-Yankees, and can’t manage but some nervous truce with their
Providence. A détente.

What is "the bottom of his blood’s avalanche"?  Does it refer to his
bloodline of "western swamp-Yankees"?