Worst flooding the region has seen in at least 20 years . NEW : At least 20 people are dead in Serbia and Bosnia - Herzegovina . More than 100 people have been killed in Croatia . More flooding is expected Sunday .
Worst flooding the region has seen in at least 120 years . NEW : At least 20 people are dead in Serbia and Bosnia-Herzegovina . More than 16,000 people have been evacuated in Serbia . More flooding is expected Sunday .