Cyclone Nisarga made landfall in District Raigad, south of Alibag, and close to Murud on 03rd June in the afternoon hours between 12 and 3 pm. The core of Mumbai escaped the fury of the storm by staying within a safe margin. After landfall, the storm kept moving NNE (north northeast) thereby increasing the distance further from the peripherals of the cyclone. Prevailing westerly winds from the sea suppressed the stormy easterly flow limiting the squally winds, both in speed and duration. Mumbai averted the sting of storm and got away with minimal damage, marginally affecting communication and connectivity.
Mumbai and neighborhood had not seen any cyclone during the month of June since 1891. However, another cyclone Phyan had struck this area in November 2009. This storm made an appearance over Konkan after 43 years (since Nov 1966). This region had the exception of hosting hat trick of cyclonic storms in 1946. The Konkan coast was battered thrice on 06 Nov (Dahanu), 11Nov (Mumbai), and 18Nov (Alibag). Another storm struck the region in 1948 also. Prior to this, another storm struck this area in Nov 1912. Historical records go on to prove November as the most active month for the cyclonic storms over the Konkan region including Mumbai.
Cyclone Nisarga caused a lot of damage at Shrivardhan in Ratnagiri and Alibag. No fatalities were reported, but few people got injured. The cyclone blew off tin and asbestos sheets from roofs and uprooted trees not just in Alibag, but in Mumbai, Thane and Navi Mumbai. Power lines and communication networks were affected resulting outages.
Cyclone thankfully skipped Mumbai without any major disruptions. Some of these aspects can be reasoned out for academic interest:
Landfall: Cyclone made landfall south of Alibag, at a fairly safe distance from Mumbai. The intensity of weather keeps reducing away from the center and particularly in the rear left quadrant. Mumbai did experience stormy conditions in few areas but averted the sting of the storm by a reasonable margin.
High Tide: On 3rd June, the high tide with a wave size of 10-12 feet was timed at 10 am and 10 pm. The landfall of the system commenced at about 12.30 pm and was completed by 3.30 pm, nearly coinciding with low tide timing. High tide along with the storm surge can result back flow thereby inundating low lying areas.
Terrain Effect: As the cyclone approaches the coast, the intrusion of drier air from the land weakens the moisture content. Cyclones draw the energy from moisture and its restricted supply degrades the system, albeit at a slow pace. This process of entrainment is universal and more coercive in the tropics.
Frictional Force: Nature of terrain and topography play a significant role in retaining the strength of the storm. Konkan coastline is contiguous to the Western Ghats with height increasing from north to south. An undulating and obstructive terrain increases the frictional impediments resulting in merely tepid support for the sustenance of storm.
Evacuation: The vulnerable areas were identified and timely evacuation of masses led to zero casualties. The fatalities on account of the felling of trees and the collapse of kutcha and weak structures were managed well. National Disaster Response Force responded well to attend to the emergent situations.
Earlier in the morning on 3rd June, a FedEx cargo plane skidded off the runway due to windy conditions and wet surfaces. As a precautionary measure, the Mumbai airport was closed till evening.
Storm threat has gone past quickly than expected. Various teams are on the job to assess the damage and provide relief wherever necessary.