Climate indices and mountain pine beetle-killing temperatures

Average minimum January temperature in British Columbia and Alberta is related to the interaction of the Pacific/North American Pattern (PNA) and the Northern Annular Mode (NAM) climate indices. Average minimum temperature at a station, modified by elevation effects, determines the number of days in the month falling below threshold levels of -20 degrees C, -30 degrees C and -40 degrees C; i.e., determines the likelihood of unseasonably low temperatures that have lethal consequences for mountain pine beetle (MPB).