Synoptic forcing and thermo-dynamical processes during cloudburst event over Sauni Binsar, Uttarakhand, India

Cloud bursts have become a pressing concern with their devastating impact and increasing frequency over the Himalayan region. Therefore, understanding the physical mechanisms associated with their occurrence is essential and urgent. Our investigation into the physical mechanisms of a cloud burst over Sauni Binsar, Uttarakhand, India, which occurred on 10 June 2021 around 06 UTC, is a step towards addressing this urgency. On the day of the cloud burst, there was a continuous accumulation/stagnation (at 850 hPa) of moist air over Sauni Binsar due to the northward propagation of the southwest monsoon, leading to atmospheric column supersaturation. The advection of warm air (dry) from the monsoon heat low at higher (700 hPa) caused potential instability over this region. Orographic lifting and a gradual increase in convergence over this region caused moist convection. Further, the analysis of Richardson's number indicated that turbulence was maximum in the middle and upper troposphere. Just a few hours before the cloud burst event (02–06 UTC 10 June 2021), the decrease in potential vorticity indicates the squashing of the moist columns and the decrease in the vorticity. The sudden squashing of the supersaturated atmospheric column might have caused enormous rainfall (Cloud burst) over the Sauni Binsar region. •Investigated physical mechanisms leading to the Sauni Binsar cloud burst.•The orographic lifting and increase in convergence caused moist convection.•The continuous trapping/accumulation of moisture caused supersaturation.•The turbulence was maximum in the mid-upper troposphere a few hours before.•Squashing of supersaturated atmospheric column caused cloud burst.