According to initial reports, evacuation process has begun. Sixty National Disaster Response Force (NDRF) personnel teams have been sent at the cyclone site for rescue and relief operations.
In an attempt to save lives, the rehabilitation process is underway.
Since morning, heavy rain accompanied by strong winds lashed coastal Andhra Pradesh.
A high alert was sounded in the coastal districts, while authorities were taking precautionary measures, including evacuation of people from low-lying area, to minimize the damage from the cyclone in the Bay of Bengal.
The Indian Meteorological Department (IMD) predicted that the severe cyclonic storm will cross the coast near Machilipatnam on Friday afternoon.
Under the influence of the severe cyclonic storm, many parts of Krishna, Guntur, East Godavari, West Godavari, Visakhapatnam and other districts were receiving rain.
The strong wind have uprooted trees, communication towers and disrupted transport and electricity supply in some parts of the coastal districts. The sea conditions were rough and the sea water at some places flushed out for a few metres over land.
The high-speed wind has damaged coconut, banana and paddy crops, and dealt another blow to farmers who are still recovering from the heavy damage caused by last month's Cyclone Phailin and accompanying heavy rain.
Cyclone Helen made a landfall at Machilipatnam coast on Friday afternoon.
The IMD has forecast rainfall at most places, and heavy to very heavy rainfall at a few places and isolated extremely heavy rainfall (25cm or more) over north coastal Andhra Pradesh and adjoining Guntur, Krishna, West Godavari districts of south coastal Andhra Pradesh over next 36 hours.
Rainfall at most places with isolated heavy to very heavy falls would occur over remaining districts of south coastal Andhra Pradesh, Rayalseema and isolated heavy to very heavy rain is expected over Telangana during next 48 hours.
Gale-speed winds reaching 100-110 kmph, gusting to 120 kmph, would sweep through Prakasham, Guntur, Krishna, East and West Godavari and Vishakhapatnam districts during the next 12 hours, the weather forecast said.
Meanwhile, Chief Minister N Kiran Kumar Reddy reviewed the situation with the chief secretary and other officials in Hyderabad and directed them to take all precautionary measures, especially in Krishna and Guntur districts.
A control room to monitor the situation has been opened at the state secretariat in Hyderabad. The control room numbers are 040-23456005, 23451043.
A control room in Krishna district collector's office was opened. Its telephone numbers are 08672-252572 08672-251077
Krishna district collector Raghunandan Rao said a holiday was declared for all educational institution in coastal areas.
He said 10 relief camps were opened for people evacuated from low-lying areas, and over 5,000 people were already shifted to them.
(With IANS inputs)