Flash Drought

• Flash Drought is the rapid onset or intensification of drought.
• A considerably long dry spell with significantly low precipitation anomalies during the monsoon result in an increase in air temperature.
• Increased air temperature and precipitation deficit together cause a rapid depletion of soil moisture leading to flash drought.
• There is little known about flash droughts or ‘hidden hazards’ when compared to research available on long-term droughts.
• Occurrence:
  • Flash droughts can occur in the monsoon season as well, primarily caused by the monsoon breaks and these can also occur due to the delayed onset of the summer.
• Duration:
  • Normally, developing drought conditions take months, but flash droughts could occur in weeks and stay on for months.
• Factors:
  • Atmospheric anomalies (variations), anthropogenic greenhouse gas emissions and ongoing climate change can lead to flash droughts.
• Detection:
  • Early-warning systems (EWS), that could identify trends in climate and sources of water, are used to detect the emergence or probability of the occurrence of flash droughts.
  • Drought monitoring through the use of remote sensing data and various indices for drought monitoring as well as through online help facilities.

Latest News about Flash Drought

• 18 April 2023:
  • As per a recent study, flash droughts occurred more often than conventional ‘slow’ droughts in tropical places like India, Southeast Asia, sub-Saharan Africa and the Amazon basin.
  • Flash droughts are fast becoming the ‘new normal‘ making forecasting and preparing for their impact more difficult.
  • Climate change has effectively speed up the onset of droughts.
  • Reason: when the precipitation suddenly shuts off, hot, sunny and windy conditions can cause large amounts of water to evaporate quickly(i.e., high evapotranspiration)
  • The trends varied from place to place, but, looked at globally, they show a shift toward more frequent and more rapid flash droughts.

Sources

1. Indian Express