Black Witch moth arrives on monsoon winds to high country

July 15, 2026

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(Ascalapha odorata) are tropical travelers that sweep northward each summer on the leading edge of monsoon moisture. One turned up on Cottonwood Trail near Gunnison on June 27 — a remarkable appearance at 7,700 feet, far from the moth's usual range. In Mexican folklore, these moths carry omens; this visitor proved uncannily prophetic.

Within days of its arrival, the river surged from just under 13 cubic feet per second to over 240 cfs, a twenty-fold spike driven by the same weather system that carried the moth north. The monsoon had arrived in earnest. For a high-altitude stream system, such a shift reshapes habitat in hours — scouring banks, flushing food chains, reordering what lives where. The moth's presence, read as omen or understood as a marker of atmospheric change, pointed toward the same threshold the water would soon cross.

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