I have the pleasure of being associated with a great research group, primarily funded through the Western Water Assessment, which is looking at the impact of forest cover change and dust intrusions on snowpack evolution and subsequent water supplies in the Colorado River basin.
We recently had a paper accepted in the Journal of Hydrology which explores the interactions between dust blowing off the desert southwest and changing snowpack albedo with mountain pine beetle (MPB) mortality, which alters a whole host of things relevant to water supplies, such as light reaching the snow, snow accumulation, snow melt (ablation), and snowpack albedo (fallen needles absorb solar energy). MPB also influences water use by the forest, changing lowering transpirational demands and making more water available for snowmelt.
All those things were fed into a spatially explicit hydrological model (DHSVM) by the lead author, who tested a variety of scenarios to see what these complex interactions added up to. Turns out there are some interesting outcomes:
Snow accumulation increases with more forest mortality, increasing runoff (though understory regeneration takes a substantial cut of that increase). Dust increases snow melt rates, making peak flow timing a bit earlier. So more water, earlier, and "peakier" (meaning more comes at once). Might have some implications for flood zones, depending on how the climate changes in regard to temperature and precipitation. Good to start teasing out the dust/forest health component of the equation now...