The cyclone cut a swathe through the coastal areas of the two states, flattening fragile dwellings, uprooting trees and electric poles, and forcing evacuation of over 6.58 lakh people.
"The forward sector of the wall cloud region is entering into land in West Bengal. The intensity of the cyclone near its centre as the landfall process started was recorded at 160-170 kmph, gusting to 190 kmph," the weatherman said.
NDRF chief S N Pradhan told a press conference in New Delhi that 20 teams of the federal disaster response force had already begun road clearing operations in Odisha, while the 19 units deployed in West Bengal were shifting people to safety.
Quoting figures made available by the two states, Pradhan said over 5 lakh people were evacuated in West Bengal and more than 1.58 lakh in Odisha.
TV footages showed gigantic tidal waves crashing into seawall in Digha, close to the scene of the landfall.
Thick sheets of rain blurred the vast coastline in the two states and surging waters engulfed mud-and-thatch houses, flattening them in a trice.
Heavy machinery was moved in to clear the roads blocked by falling trees.
India Meteorological Department (IMD) Director General Mrityunjay Mohapatra, who jointly addressed the media with Pradhan, said gale-strength winds speeding at 160-170 kmph were pounding South and North 24 Parganas and East Midnapore districts and could be gusting up to 185 kmph.
He said the eye of the monster cyclone, the most explosive part of the cyclonic system, had touched the land, triggering copious rain in the three districts. The eye of the storm itself was 30 km in diameter, he said.
Mohapatra said the intensity of the rain and winds accompanying it could deceptively look like ebbing away briefly, but will surge afresh once the rear sector of the storm has reached the landmass.
The whole cyclonic system will have reached the land by 7 pm, he said.
Reports arriving in Kolkata from North and South 24 Parganas and East Midnapore said roofs of thatched houses were blown away, and twisted electric poles and broken and uprooted trees bore testimony to the devastation. Streets and homes in low lying areas of Kolkata were swamped with rainwater.
Mohapatra said the storm will reach Kolkata in all its fury later in the evening and winds blowing at 110-120 kmph, and gusting at 135 kmph, coupled with downpour, will batter the capital city.
Despite losing its force a bit since Tuesday, the storm, which was categorised as super cyclone at one point of time, has left the two eastern states on edge as it hollered on its destructive path over the Bay of Bengal.
Intense rainfall was recorded in several areas of Puri, Khurda, Jagatsinghpur, Cuttack, Kendrapara, Jajpur, Ganjam, Ganjam, Bhadrak and Balasore districts since Tuesday.
The rains and high-velocity winds will ebb away in Odisha by late Wednesday night by when the cyclone will likely have caused massive damage to standing crops, plantations and infrastructure, Mohapatra said.
He said tidal surge of up to five metres could occur in North and South 24 Parganas and East Midnapore districts that could submerge areas in a radius of 15 km.
The strong winds and rain could continue till tomorrow in West Bengal, he said.
The turbulence will likely extend to Assam and Meghalaya, triggering heavy to very heavy rain on Thursday.
Mohapatra said since the time the depression formed over the Bay of Bengal on May 20 till the cyclone made the landfall, the IMD's predictions about the path it will take and the timing was accurate and helped the disaster response machinery strategise and execute the plans to minimise the damage effectively.
The cyclonic storm will get weaker while crossing over Nadia and Murshidabad in West Bengal later tonight before entering Bangladesh as a deep depression and dissipating.