Trees were uprooted disrupting traffic and communication and electricity towers were damaged as strong gales with speed reaching 100-110 kmph caused havoc in the coastal districts of Krishna and two Godavari districts.
The deaths were mostly caused by falling trees in the affected districts, said officials.
The sea conditions were rough and the sea water at some places flushed out for a few metres over land.
According to Visakhapatnam Cyclone Warning Centre, the cyclone made the landfall near Machilipatnam in Krishna district around 2 p.m. Officials said it would take some more time for the entire system to cross the coast.
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 Indian Meteorological Department (IMD) has warned that storm surge of about 1 to 1.5m height would inundate the low-lying areas of West and East Godavari, Krishna, Guntur districts and adjoining areas of Prakasham district.
The IMD has warned that even after landfall the storm is likely to maintain the intensity for six hours and gradually weaken into a deep depression in subsequent six hours while moving westwards across coastal Andhra Pradesh and Telangana.
With heavy rains likely to continuing in coastal districts over next 36 hours, authorities have evacuated 17,000 people from low-lying areas.
C. Parthasarathi, commissioner, disaster management, said 66 relief camps were opened.
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.
Rainfall at most places with heavy to very heavy rainfall at a few places and isolated extremely heavy rainfall (25cm or more) would occur over north coastal Andhra Pradesh and adjoining Guntur, Krishna, West Godavari districts of south coastal Andhra Pradesh during next 36 hours, said a bulletin by the IMD.
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 falls over Telangana during next 48 hours.
Earlier, Chief Minister N. Kiran Kumar Reddy Friday 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.
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. Sixty personnel of National Disaster Response Force (NDRF) personnel were deployed for rescue and relief operations.
A control room in Krishna district collector's office was opened. Its telephone numbers are 08672-252572 08672-251077
Helen has hit the Andhra coast even before the state could recover from the massive damages caused by Phailin and heavy rain in October.
Andhra Pradesh has nearly 1,000-km long coastline and the nine districts face cyclone threats every year, especially between September and November.