Epilobium howellii is an uncommon species of flowering plant in the evening primrose family known by the common names Yuba Pass willowherb and subalpine fireweed (though it is not a true fireweed). It is endemic to the High Sierra Nevada of California, where it is known from only about 20 occurrences. It grows in wet mountain habitat such as meadows, often in the presence of mosses and willows, between 2000 and 2700 meters in elevation. The plant was first collected in 1975 at Yuba Pass on Highway 49 in Sierra County, California, and described to science as a new species in 1992.