Dougherty et al. (2025) Historical Warming and Drying in Colorado and Their Impact on Cool-Season Precipitation and Snow

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Identification

• Journal: Journal of Hydrometeorology
• Year: 2025
• Date: 2025-07-25
• Authors: Erin Dougherty, Sarah A. Tessendorf, Amy DeCastro
• DOI: 10.1175/jhm-d-24-0153.1

Research Groups

Not specified in the provided text.

Short Summary

This study evaluates thermodynamic changes in Colorado and the Gunnison River basin from 1981 to 2021, finding that warming and drying have led to decreased snowfall and accelerated snowmelt.

Objective

• To assess how thermodynamic changes over the past 40 years have altered precipitation patterns, the frequency of dry days, snow accumulation, and ablation in the headwaters of the Colorado River.

Study Configuration

• Spatial Scale: Colorado state and the Gunnison River basin (headwaters of the Colorado River).
• Temporal Scale: 1981–2021.

Methodology and Data

• Models used: High-resolution model with a 4-km grid spacing.
• Data sources: Model data evaluated against observational datasets.

Main Results

• Precipitation and Snowfall: Observed a decrease in snow days (up to 5 days per winter) and an increase in dry days (up to 6 days per winter).
• Snow Water Equivalent (SWE): Peak SWE decreased at a rate of $-2.1\text{ mm yr}^{-1}$ in the model and $-3.4\text{ mm yr}^{-1}$ in observations.
• Ablation: Ablation days increased by up to 4 days per winter, particularly at altitudes exceeding $3000\text{ m}$.
• Ablation Drivers: At high altitudes, dry days contributed 85% to ablation, while rain days contributed 20%.
• Temporal Trend: The contribution of dry days to ablation was higher during the 2001–2021 period than during the 1981–2001 period.

Contributions

• Demonstrates that water resources in the Colorado River headwaters have already undergone significant changes due to climate-induced warming, providing high-resolution evidence to support the necessity of urgent water resource planning.

Funding

Not specified in the provided text.

Citation

@article{Dougherty2025Historical,
  author = {Dougherty, Erin and Tessendorf, Sarah A. and DeCastro, Amy},
  title = {Historical Warming and Drying in Colorado and Their Impact on Cool-Season Precipitation and Snow},
  journal = {Journal of Hydrometeorology},
  year = {2025},
  doi = {10.1175/jhm-d-24-0153.1},
  url = {https://doi.org/10.1175/jhm-d-24-0153.1}
}