Severe flooding and landslides have killed at least 20 people in northern Philippines' Zambales province. Monsoon rains, caused by typhoon Usagi, destroyed homes and displaced thousands of people. Hundreds of residents have been stranded on rooftops, and many coastal communities remain cut off from the rest of the province. At least 6,000 people are now living in evacuation centres with barely enough food and drinking water. Al Jazeera's Jamela Alindogan reports from northern Zambales province.