Short term dryness indicator

(For the 21 days to 30 April 2025)

The highest Relative Soil Water values (above 80%) are currently being observed in the northeast of the state.

The 21-day Relative Soil Water indicator is a short-range physical drought indicator for detecting rapid drying events. It is calculated by using the 21-day rolling mean of daily modelled rootzone soil moisture (mm) and normalises that, relative to the water holding capacity (drained upper limit) of the soil at that location.

While it is an indicator that is a closer reflection of field conditions at the time of observation, it is also more volatile (changes rapidly). This contrasts to the SWI which is less sensitive to short range variability and designed to detect long term seasonal conditions.