Soil monitoring tool detects flash droughts

By Scout Nelson

A new satellite-based tool, FLASH (Flash Drought Assessment using SMAP Hydrology), offers early warnings to help farmers and water managers anticipate flash droughts. Developed by soil hydrology researchers Vinit Sehgal and Binayak Mohanty using NASA's Soil Moisture Active Passive (SMAP) data, FLASH monitors soil moisture levels in near real-time to detect emerging drought conditions.

Flash droughts are rapidly intensifying droughts that can devastate crops and pastures in a short time, as witnessed in 2017 when farmers in Montana and the Dakotas faced over $2.6 billion in crop losses due to unexpected dry conditions. Unlike traditional drought monitoring, which relies on monthly or weekly data, FLASH provides daily updates, giving farmers the advance warning needed to implement adaptive measures.

Sehgal and his team, including researchers from Texas A&M University and the University of Georgia, used SMAP satellite data from 2015 to 2021 to build the FLASH tool. The SMAP data assesses the top 5 cm of soil moisture across large regions, so the team developed an index called the Flash Drought Stress Index (FDSI) to gauge when soil moisture levels are nearing critical dry points.

To create this predictive tool, researchers mapped soil drying patterns based on soil moisture data. They identified two key points: the critical point, where plants struggle to extract water, and the wilting point, where plants can no longer survive. Once the soil nears these points, FLASH alerts farmers to potential flash droughts, allowing them to take preventive actions like irrigating, adjusting planting schedules, and managing pests.

Despite the success of FLASH, challenges remain. The SMAP satellite data only monitors surface moisture, not deeper moisture levels that farmers typically need. Additionally, dense vegetation, such as in Louisiana, limits FLASH's effectiveness. The research team is working to expand FLASH’s coverage, with hopes of including ground sensors for improved accuracy in these regions.

This breakthrough in soil moisture monitoring is vital as climate change increases the frequency of extreme weather events. The rapid intensification of droughts directly impacts agriculture, raising food prices and threatening crop yields.

FLASH’s early warnings empower farmers to prepare for flash droughts and mitigate losses, aiming to make communities more resilient in a changing climate.

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