HAPpy Hour Seminar : From Snowfall to Streamflow: Field Campaigns, Seeding Strategies, and Modeling Progress in Winter Weather Modification

Abstract : A renewed era of cloud seeding research is underway, building on the momentum of the SNOWIE field campaign. This seminar presents a unified look at recent and ongoing efforts across the western U.S. to better understand and optimize wintertime cloud seeding. The talk will highlight two concurrent field campaigns: the Seeded and Natural Orographic Winter Storms and Catchment Processes Evaluation Project (SNOWSCAPE) in Utah’s northern Wasatch Mountains, and the Liquid Propane Experiment (LPX) in Idaho’s Camas Prairie. Each is designed to capture the physical signatures of seeded and natural snowfall across distinct meteorological regimes and terrain.
SNOWSCAPE is the first major field campaign to incorporate drone-based cloud seeding using powdered silver iodide. LPX focuses on liquid propane, a glaciogenic agent effective at warmer temperatures than silver iodide, broadening the range of seedable conditions. LPX also investigates anomalous easterly wind events in the Snake River Plain, which may present new opportunities for seeding under atypical flow regimes.

Observations from both campaigns will support the integration of seeding processes into WRF-WxMod, enabling physics-aware simulations of cloud seeding impacts. These efforts lay the groundwork for coupling with WRF-Hydro, allowing quantification of seeding effects on streamflow and water resources.

Finally, the seminar introduces a novel evaluation framework using Analog Ensembles as a modern alternative to traditional Target-Control methods. This approach leverages reanalysis datasets to generate analogs from non-seeded periods, providing robust statistical comparisons and site-specific assessments of potential seeding benefit.

Together, these efforts represent a holistic strategy to advance the science, modeling, and real-world evaluation of wintertime cloud seeding in complex terrain.

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