It occurs in the Columbia Basin in Washington and northern Oregon.

The dorsal hindwing is slightly brownish gray, darker and grayer on the distal half, with a gray ill-defined oval discal spot and a thin terminal line.

Adults are on wing from late April to early June.

The name is derived from the Latin diluvium (meaning deluge or flood).

The Columbia Basin where this moth occurs in Washington was scoured repeatedly by cataclysmic floods at the end of the Ice Age.