English: "a, The reconstruction extends back to 1400 ce underlining high year-to-year variability with extreme long-lying and early-melting snowpack duration (black curve), a long-term variability (green dashed curve, 50 yr spline filter) ending with the clear decline starting in the last century (orange curve; piecewise linear regression fit to the reconstruction). Grey band represents the estimation of uncertainty of the reconstruction (±2 root mean square error). b, Detail over the common period (1834–2018) of the ring-width reconstruction (black curve) with the modelled duration of yearly snow cover (blue curve) and the instrumental data (red curve) represented by the mean value of the snow cover duration records for the stations within a distance of 50 km and an elevation of ±250 m from the study site (n = 6). Stations data have been rescaled with respect to the study site mean modelled snow cover value before comparison."