Figure 3

Accumulation rate time series from 810 CE to the present after correction by four independent layer-thinning model approaches: Campbell¹⁴ (black), Hawley (blue), Thompson^13,18,19,20 (green) and Hooke¹² (red); see supplementary information for details about each. Y-axes are equivalent in each panel, ranging from 0 to 1.5 meters of water equivalent annual accumulation. Results are smoothed with a 21-year running mean for clarity. Shading indicates the full range of accumulation estimates produced among different scenarios in each model. The central estimate in the Campbell model is shown for comparison in the bottom three panels as a dotted line. Every model shows unprecedented levels of snow accumulation in the 20^th century under any set of plausible input parameters.