Hecate Strait, off the northwest coast of British Columbia, a body of water unusually shallow for its size, is prone to surprise storms of unpredictable ferocity and duration. It is a fascinating body of water, and the inspiration for Hecate Nocturne, for Large Orchestra, a one-movement orchestral evocation of a day on Hecate Strait’s waters. The piece incorporates birdsong from the region, as well as First Nations folksong, rendering a soundscape uniquely British Columbian. The calm, mystery, and excitement of the music will appeal to concert-going audiences, especially to those interested in the sounds of British Columbia, and the piece is of only moderate difficulty for a large orchestra. The full orchestral conductor’s score is given. In addition, a detailed analysis, by the composer, is included, for orchestral directors, music theoreticians, students of composition, and interested musicians. It reveals the means of construction of Hecate Nocturne, so that the reader may understand better its harmonies, melodies, form, and sound effects.