Figure 4.4. Dependence of trends in snow on mean winter temperature (°C) at each location. (a) Relative trends in 1 April SWE, 1950 to 2000, in the mountains of western North America (British Columbia, Washington, Oregon and California), binned by mean December to February (DJF) temperature. For each 1°C temperature bin, ‘×’ symbols indicate the mean trend, bars indicate the span of the 5 to 95% confidence interval for bins with at least 10 points, and circles indicate outliers. Total number of data points is 323 (adapted from Mote et al., 2005). (b) Relative trend in days of winter (DJF) snow cover at 109 sites in Switzerland, 1958 to 1999, binned by mean DJF temperature (adapted from Scherrer et al., 2004).