Global snow drought hot spots and characteristics

Area of Science:

• Hydrology
• Climate Science
• Environmental Science

Background:

• Snow droughts, defined by snow water equivalent deficits, are critical but globally unassessed phenomena.
• Changes in snow drought duration and intensity significantly impact water resources, ecosystems, and socioeconomic stability.

Purpose of the Study:

• To conduct the first global assessment of snow drought duration and intensity from 1980 to 2018.
• To identify regional 'hot spots' of increasing snow drought prevalence and intensity.
• To establish a framework for improved snow drought monitoring and assessment.

Main Methods:

• Analysis of global snow water equivalent (SWE) data from 1980 to 2018.
• Characterization of snow drought duration and intensity metrics.
• Comparison of snow drought characteristics between the first and second halves of the study period.

Main Results:

• Snow droughts intensified and lengthened across the Western United States, Eastern Russia, and Europe.
• Specific regions like the Western US, Europe, and Eastern Russia showed significant increases in snow drought duration and probability of exceeding average intensity.
• Conversely, regions including the Hindu Kush, Central Asia, extratropical Andes, Himalayas, and Patagonia experienced decreased snow drought durations.

Conclusions:

• Snow drought characteristics have significantly changed globally, with notable increases in some regions and decreases in others.
• Physical processes such as Arctic amplification and polar vortex dynamics likely influence observed snow drought trends.
• The developed framework aids in monitoring and assessing snow deficits, as demonstrated by case studies from the Western US and Afghanistan.