Categorization of Rainfall Intensity [mm in one(1) hour]
Light ( 0.5mm - 10mm ),
Moderate ( 11mm - 30mm ),
Heavy ( 31mm - 60mm ),
Very Heavy ( >60mm )
Notes:
Convective rain more than 60mm in 2 to 4 hours duration (typical) may cause flash floods.
However, monsoon rains are typically of long duration with intermittent heavy bursts and the intensity can occasionally exceed several hundred mm in 24 hours.