Date of Award

Summer 2026

Language

English

Embargo Period

7-31-2026

Document Type

Master's Thesis

Degree Name

Master of Science (MS)

College/School/Department

Department of Atmospheric and Environmental Sciences

Program

Atmospheric Science

First Advisor

Justin Minder

Second Advisor

Brian Tang

Keywords

Snowmelt, Atmospheric River, Flooding, Catskills, Extreme Precipitation, Energy Budget

Subject Categories

Atmospheric Sciences | Meteorology

Abstract

This study uses atmospheric reanalysis, precipitation and snow water equivalent (SWE) analyses, mesonet observations, and streamflow records to examine the impact of an atmospheric river storm that produced heavy rainfall and snowpack ablation across the Catskill Mountains of New York on 24–25 December 2020. Earlier in December, an antecedent storm produced SWE values in the Catskills above the 90th percentile for that point in the season. The atmospheric river event followed with strong southerly warm-air advection ahead of an anomalously deep trough, temperatures and dewpoints that exceeded 10°C, and heavy orographically enhanced rainfall and rapid snowmelt. Sensible heat fluxes were the primary contributions to snowmelt energy, while latent heat fluxes and advective energy from rainfall were secondary.

The rapid snowmelt and heavy rainfall resulted in the Esopus Creek, which provides inflow to New York City’s Ashokan Reservoir, reaching 10-year return interval streamflow magnitudes. Streamflows into six of New York City’s reservoir catchments over the Catskills were partitioned by estimating catchment-integrated rainfall and SWE loss volumes for this event and other overlapping extreme SWE loss and streamflow events from water years 2004–2024. In the 24–25 December 2020 event, snowmelt accounted for ~30–50% of total streamflow volume. In comparison with other overlapping extreme SWE loss and streamflow events, 24–25 December 2020 was distinguished primarily by its large rainfall accumulations. Events with greater SWE losses, but limited rainfall produced comparatively muted discharge volumes. Synoptic analysis of these events showed all overlapping events occurred during objectively identified AR conditions.

License

Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.

Download

Share

COinS