MANILA, Philippines — Raging floodwaters following days of rain in the eastern Philippines have drowned an 80-year-old woman and her son and sent some 33,000 people to evacuation centers.

Authorities declared a state of calamity in the worst-hit Albay province, where thousands of residents in seven towns including those living on the slopes of the Mayon volcano moved to emergency shelters after landslides and floods cut off roads and overflowed river banks.

Disaster official Bernardo Rafaelito Alejandro said the woman and her son died while crossing a flooded area in Manito township late Wednesday when a strong current swept them away. Tens of thousands of people were evacuated on Thursday.