Eric Gagliano

Eric Gagliano

Postdoctoral Scholar, Terrain Analysis and Cryosphere Observation Lab

University of Washington

Remote sensing · Cryosphere · SAR

I'm a postdoctoral researcher at UW CEE's Terrain Analysis and Cryosphere Observation Lab, with a research focus on understanding when and where mountain snowmelt occurs — a critical question for the more than one billion people who depend on seasonal snowpack for freshwater. I graduated from UW with my PhD in December 2025, and my dissertation work combined satellite radar remote sensing with large-scale cloud computing to produce the first global, high-resolution record of snowmelt runoff onset timing, processing ~3.9 million Sentinel-1 C-band SAR scenes at 80-meter resolution from 2015 to 2024. This dataset enabled a systematic analysis of elevation, aspect, and temperature controls on snowmelt timing patterns across ~150 mountain ranges.

As a postdoc, I'm continuing to work on snowmelt phase delineation and wet snow detection, and I'm developing and evaluating snowmelt methods that leverage data from NASA's newly launched NISAR L-band SAR mission. I'm also building scalable, automatically-updating geospatial data pipelines using emerging tools like Icechunk and GitHub Actions. Alongside research, I develop and maintain open-source Python tools to make snow-related geospatial datasets more accessible to the broader community. I'm passionate about teaching — I've taught UW's graduate Geospatial Data Analysis in Python (CEE 467/CEWA 567) twice and TA'd often — and hope to eventually transition to a public high school teaching role.

Ten-year median snowmelt runoff onset date across the Northern Hemisphere

Global snowmelt runoff onset — Sentinel-1 SAR dataset

A 10-year (2015–2024), 80-meter resolution global dataset of annual mountain snowmelt onset timing derived from ~3.9 million Sentinel-1 SAR scenes. Covers ~150 mountain ranges and is validated against 900+ SNOTEL/CCSS weather stations. The dataset reveals global patterns in snowmelt timing and their links to climate variability.

Global MODIS snow phenology

Global MODIS snow phenology

A global, 500-meter resolution snow phenology dataset derived from a decade (2015–2024) of MODIS 8-day maximum snow extent observations. Explore snow appearance, disappearance, and duration for any location and year, with cloud-gap filling and polar-region corrections applied.

Global snow networks

Global snow networks

A station archive and Python toolkit for snow point observations — snow water equivalent and snow depth from automated pillows, manual snow courses, aerial markers, and mirrored climate stations across nine networks in the United States, Canada, and Norway. CSV-first and automatically updating, with a live map of every daily-reporting station.

Binary wet snow maps derived from Sentinel-1 backscatter

Capturing mountain snowmelt with SAR

The research prototype behind the global dataset: Sentinel-1 C-band backscatter change-point analysis to detect snowmelt runoff onset across Western U.S. mountain ranges, and the first systematic evaluation of SAR-derived snowmelt timing against in-situ records.

Global tile processing status grid, all 381 tiles complete

Icechunk + GitHub Actions demo

Building a global-scale raster dataset with GitHub Actions for parallel compute and Icechunk for versioned, conflict-free Zarr storage. Hundreds of concurrent runners process MODIS land surface temperature across 376 tiles worldwide — 753 GB in about 40 minutes — visualized in an interactive web map.

easysnowdata

easysnowdata

A Python package that makes it easy to access snow-related geospatial datasets — including SNOTEL/CCSS station records, MODIS snow products, SAR-derived snowmelt timing, and more. Designed for researchers and practitioners working with snowpack data at scale.

SNOTEL and CCSS station archive

snotel_ccss_stations

A curated archive of SNOTEL and CCSS station metadata and daily records, with convenient Python access utilities for snow water equivalent and snowmelt validation studies. Superseded by Global snow networks, which extends the same approach to nine networks.

Sentinel-1 local incidence angle maps

Sentinel-1 local incidence angle maps

Tool for generating per-pixel local incidence angle maps for Sentinel-1 SAR imagery, useful for terrain correction in mountainous areas.

Sentinel-1 over a snow-covered mountain range

spicy-snow

A collaborative SnowEx project for snow depth estimation from Sentinel-1 cross-polarization SAR. Developed during SnowEx HackWeek 2022 and continuing as an active open-source project.

UW Geospatial Data Analysis course

Geospatial Data Analysis in Python — course JupyterBook

Open-access course materials for CEE 467/CEWA 567 at UW, which I designed and teach. Covers vector and raster data processing, remote sensing, and cloud-based geospatial workflows in Python. New cohort each winter quarter.

Gagliano, E., Shean, D., & Henderson, S.

Global patterns and controls on mountain snowmelt runoff onset from a decade of high-resolution observations

Mower, R., Pflug, J. M., Gagliano, E., Gutmann, E., Cristea, N., & Lundquist, J. D.

Identifying wet pixels for SAR-based SWE retrieval using model output and Sentinel-1 backscatter signals

Mirza, B., Gagliano, E., Small, E., & Raleigh, M.

Remotely sensed melt fraction enhances streamflow modeling in snow-dominated ungauged basins with long short-term memory networks

Hydrological Processes · preprint: 10.2139/ssrn.6675822

Brencher, G., Shean, D., Henderson, S., & Gagliano, E.

Accurate snow depth predictions across the Western U.S. using a deep learning model trained on 7 years of airborne lidar snow depth measurements

preprint: 10.2139/ssrn.6557436

Global snowmelt runoff onset composite

Gagliano, E., Shean, D., & Henderson, S.

A global high-resolution dataset of snowmelt runoff onset timing from Sentinel-1 SAR, 2015–2024

Earth System Science Data, 18(8), 5871–5894 · 10.5194/essd-18-5871-2026

Bennett, M. M., & Gagliano, E.

Breaker of images: Synthetic aperture radar and satellite iconoclasm

Environment and Planning F (online first) · 10.1177/26349825261456297

Kaur, P., Webb, R., Tarricone, J., Rittger, K., McGrath, D., Gagliano, E., Palomaki, R. T., Bonnell, R., Forster, R., & Marshall, H. P.

Feasibility mapping of L-band InSAR for SWE retrievals across the Western United States

Geophysical Research Letters, 53(10), e2025GL120162 · 10.1029/2025GL120162

Rickenbaugh, L., Sproles, E., Gagliano, E., Covino, T., Tuholske, C., & Carroll, R. W. H.

When and where does water originate? Leveraging stable water isotopes and synthetic aperture radar to assess the hydrology of a snow-dominated watershed in southwestern Montana

Remote Sensing Applications: Society and Environment, 41, 101887 · 10.1016/j.rsase.2026.101887

Detre, A., McGrath, D., Gagliano, E., Bonnell, R., Webb, R., Marshall, H. P., & Shean, D.

Sentinel-1 SAR estimates of snowmelt onset coincide with SNOTEL soil moisture pulses across the Western United States

Hydrological Processes, 39(12), e70341 · 10.1002/hyp.70341

Snow volume scattering schematic

Hoppinen, Z., Palomaki, R. T., Brencher, G., Dunmire, D., Gagliano, E., Marziliano, A., Tarricone, J., & Marshall, H. P.

Evaluating snow depth retrievals from Sentinel-1 volume scattering over NASA SnowEx sites

The Cryosphere, 18(11), 5407–5430 · 10.5194/tc-18-5407-2024

Gagliano, E., Shean, D., Henderson, S., & Vanderwilt, S.

Capturing the onset of mountain snowmelt runoff using satellite synthetic aperture radar

Geophysical Research Letters, 50(21), e2023GL105303 · 10.1029/2023GL105303

Rogic, N., Charbonnier, S. J., Garin, F., Dayhoff, G. W., II, Gagliano, E., Rodgers, M., Connor, C. B., Varma, S., & Shean, D.

Characterizing and mapping volcanic flow deposits on Mount St. Helens via dual-band SAR imagery

Remote Sensing, 15(11), 2791 · 10.3390/rs15112791