Science Source

Twenty-First-Century Snowfall and Snowpack Changes over the Southern California Mountains

Projects future snowfall and snowpack changes over the mountains of Southern California using a new hybrid dynamical–statistical framework
Analyses variables pertaining to snow for the middle (2041–60) and end (2081–2100) of the twenty-first century under two representative concentration pathway (RCP) scenarios: RCP8.5 (business as usual) and RCP2.6 (mitigation)
Compares these four sets of projections with a baseline reconstruction of climate from 1981 to 2000
Finds that for both future time slices and scenarios, ensemble-mean total winter snowfall loss is widespread
- By 2041–60 under RCP8.5, ensemble-mean winter snowfall is about 70% of baseline
- By 2041–60 under RCP2.6, ensemble-mean winter snowfall is somewhat higher at about 80% of baseline
- By 2081–2100 under RCP8.5, winter snowfall is about 50% of baseline
- By 2081–2100 under RCP2.6, only a negligible further reduction from midcentury snowfall totals is seen
States these figures are all associated with large intermodel uncertainty because of the spread in the GCM climate projections
Assesses snowpack on the ground, as represented by 1 April snow water equivalent
States the loss seen in snowpack is generally 50% greater than that seen in winter snowfall because of enhanced snowmelt
Finds that by midcentury under RCP8.5, warming-accelerated spring snowmelt leads to snow-free dates that are about 1–3 weeks earlier than in the baseline period