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Drought Indices and Indicators for the Northeast: September 7, 2021

Event Date
September 7, 2021
Event Time
1:00 pm - 2:30 pm

This webinar shared project findings on drought indices and indicators that support the monitoring and management of different drought types in the northeast United States. The objective of this two-year project was to identify the most effective drought indicators for hydrologic and agricultural drought monitoring in the NIDIS Northeast Drought Early Warning System (DEWS). This includes identifying appropriate time scales related to long-term and short-term drought, and identifying responsive indicators of flash drought development. Another objective was to quantify historical snow droughts, including determining the most appropriate methods and data sources for snow drought analysis given the lack of monitoring stations that measure snow water equivalent, and identifying impacts from summer droughts.

This webinar was held by NIDIS, the Desert Research Institute (DRI), and Cooperative Institute for Research in Environmental Sciences at the University of Colorado Boulder (CIRES), in cooperation with the Northeast Regional Climate Center (NRCC).



Speaker: Sylvia Reeves, NOAA's National Integrated Drought Information System (NIDIS); Cooperative Institute for Research in Environmental Sciences (CIRES)

  • Today's presentation highlights one of many drought research efforts that focus on improving our drought early warning capacity.
  • I'd like to introduce the project lead, Dr. Dan McEvoy, a regional climatologist at the Western Regional Climate Center and Desert Research Institute.



Introduction to Drought Indicators and Indices Project

Speaker: Dan McEvoy, Desert Research Institute, Western Regional Climate Center

  • We are wrapping up a multi-year project funded through NOAA's Climate Program Office and NIDIS: Identifying Time Scales and Tools to Support the Northeast DEWS and Management of Different Drought Types.
  • Today, we'll cover some of the research highlights from this project.
  • Project Objectives:
    • Identify the most effective drought indicators for hydrological and agricultural drought monitoring in the Northeast Drought Early Warning System (DEWS) region.
    • Understand how this information can be used to strengthen the Northeast DEWS and be incorporated into management planning, and decision making.



Drought Index Relationships to Crop Health

Speaker: Shuang Xia, Desert Research Institute

  • There are strong connections between crop yield and drought indices in the Northeast.
  • Such connections vary by region and season, depending on local climate features and crop cycles.
  • Crop conditions in most states show 2016 and 2020 as the worst two drought years for crop health on record.
  • Within these two years, 1–3 months of excess evaporative demand and precipitation deficit are most responsible for the degradation, with the timescale for evaporative demand slightly shorter than precipitation.
  • We hope that the findings of this study can contribute to better drought monitoring and prediction in the Northeast DEWS and contribute to the U.S. Drought Monitor.



Quantifying Snow Droughts in the Northeast U.S.

Speaker: Dan McEvoy, Desert Research Institute, Western Regional Climate Center

  • Snow course data combined with gridded weather data can be used to examine historical snow droughts.
  • 1980 snow drought: Driven by a lack of precipitation.
  • 2012 and 2016 snow droughts: Driven by well-above-normal temperatures.
  • Limited snow water equivalent (SWE) observations makes tracking snow droughts in the Northeast challenging.
  • Gridded SWE data can be useful for tracking daily snow drought conditions.
  • Resources for tracking snow droughts:



Tracking Flash Droughts in the Northeast U.S.

Speaker: Mike Hobbins, NOAA Physical Sciences Laboratory, CIRES

  • The Northeast drought of 2020:
    • We saw multiple fluxes and states indicating flash drought before the U.S. Drought Monitor.
    • Was winter- and spring-time elevated evaporative demand a precursor to this drought?
    • If we had better early warning, would we not have indicated this as a flash drought? Would we have spotted it earlier?
  • Science issues:
    • When examining flash drought, it is important to examine multiple indices bracketing the hydrologic cycle.
    • There are soil moisture issues. If you're going to use soil moisture, you need to use a high-resolution soil dataset and determine which one is best for your region.
    • Use existing drought indices carefully in flash drought detection.
    • NIDIS Flash Drought Virtual Workshop
    • The research community is not ready to provide a flash drought definition. We are relying on these principles of rapidity of onset, dryness, and impacts.
  • User issues:
    • The decision time-frame might be best to identify flash droughts, until we reach a definition.
    • Need to determine whether responses should be different during flash drought vs. conventional droughts.
    • Researchers must work together with decision makers and operational monitors.
    • Users need the ability to pick from a variety of indices and definitions to satisfy their sector-specific and region-specific needs.



Q&A Session