Lilongwe - Malawi President Peter Mutharika has declared half the southern African country a disaster zone after torrential rains over the past few days killed at least 48 people and left around 70 000 homeless.The heavy rains have also damaged crops in the country, which last year harvested a bumper 3.9 million tons of the staple maize crop, a surplus of almost a million tonnes.Malawi's department of climate Change and Meteorological Services has warned of heavy rainfall and flash floods in the country for the next two to three weeks."So far, it is estimated that 69 995 people have been displaced by the floods and 48 people have lost their lives. The floods have also damaged a lot of hectares of crops, washed away livestock and damaged infrastructure such as roads and bridges,"Mutharika said in a statement late on Tuesday.Prolonged heavy rainsHe also said many people remained stranded and would need to be rescued from low-lying areas prone to flooding."I declare all the 15 districts that have been affected by floods Disaster Areas... I appeal for humanitarian assistance, from the international donor community," he said.The crop outlook in the country, where much agriculture is still done by subsistence farmers, has deteriorated after a late start to rains in the summer planting season which usually gets underway in October or November."Delayed and overall below-average cumulative rains since the start of the rainy season in October last year have adversely affected the 2015 cereal crops, but prolonged heavy rains may worsen the situation," said Jeffrey Luhanga, Principal Secretary in the Ministry of Agriculture.Wet weather has also wreaked damage in neighbouring Mozambique, which has been hit periodically by catastrophic floods in the past.Bridges have collapsed in the country and the newly elected government there has declared a "red alert" for the central and northern parts of the country and was sending rescue boats and aid to stricken areas.