Timeline of Elevation of Freezing Temperature in January

Graph showing landslides that occurred when the elevation of the freezing temperature in the center of the northern half of the study area was below the average elevation (blue bars) and above the average elevation (red bars). The clusters are highlighted in yellow. (Temperature data is from the North American Freezing Level Tracker (NAFLT).) The question marks signify that the start and end times for the first and last clusters (respectively) are not known. The clusters in this study occured when the temperature on the upper slopes was higher than normal for successive years.