Geoenvironmental Disasters

Table 1 Precipitation excess (wet) or deficit (dry) severity class according to SPI values and corresponding D-scale

From: Spatial and temporal appraisal of drought jeopardy over the Gangetic West Bengal, eastern India

SPI values	Draught severity class	D-Scale
2.0+	Extremely wet	W3
1.5 to 1.99	Very wet	W2
1.0 to 1.49	Moderately wet	W1
−.99 to .99	Near normal	N
−1.0 to −1.49	Moderately dry	D1
−1.5 to − 1.99	Severely dry	D2
−2 and less	Extremely dry	D3

Source: Based on the user guide of the WMO 2012 (URL: http://www.wamis.org/agm/pubs/SPI/WMO_1090_EN.pdf)

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