Dave Bonta watches a slab of snow slide off a tin roof and sees something alive in it. After sun melts the snow and a cold night refreezes it, the mass holds together as it slips over the edge, curling under the eaves into "a white claw." From there the poem's imagination takes off: the roof's corrugations become a Siberian tiger's stripes, and the house becomes a fort the animal is "hell-bent" on escaping. The icicles add to the picture, their tips like daggers, their drips like saliva.
The speaker seems fascinated more than frightened. The tone is observant and a little playful, as the comparisons pile up. But the ending shifts. The "wavy sky" signals a clash of dry and wet, "unsettled weather," and the last line, "An ambiguous threat," leaves things uneasy. The danger is half joke, half real, and the poem doesn't settle which.