Hydrological and Meteorological Drought Monitoring and Trend Analysis in Abbay River Basin, Ethiopia

Table 3

Hydrometeorological drought category based on SPI, RDI, and SDI values [58].

SPI, RDI, and SDI ranges	Drought categories
>2	Extremely wet
1.5–1.99	Severely wet
1.0–1.49	Moderately wet
−0.99–0.99	Near normal
−1.0–−1.49	Moderate drought
−1.5–−1.99	Severe drought
<−2	Extreme drought