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A robust hairy medium-sized (approximately 4.5 cm wingspan) grey moth with black markings. Forewings grey with dull black lines and streaks. The antemedian and postmedian lines are complete, the former erratic and the later arcing basad near the costa. The claviform spot is outlined in black, as are the veins, and there are short black streaks running to the margin between the veins. The hind wings are white with a light dusting of grey. The veins are lined with dark scales, there is a prominent dark discal lunule, and a dark terminal line broken at the veins. Fringe white. Sexes similar but male antennae pectinate, female simple or serrate. Adults and genitalia of both sexes are illustrated in Poole (op. cit.)

Poorly known. There is a single annual brood, with adults on the wing in early spring (mid-April through early May). The larvae are described in Poole (op.cit.). Larvea have been reared from blueberry (Vaccinium angustifolium Ait.). Birch is a favored host of related B. nebulosa in Europe, and we suspect it is also a host of borealis in North America.

Maine and Pennsylvania west to central Alberta. In Alberta it has been collected along the southern edge of the boreal forest west to the Holmes Crossing sandhills near Ft. Assiniboine and the Red Deer River valley at McKenzie Crossing, west of Big Valley.