Cyclone Idai has killed an estimated 750 people in the countries of Malawi, Zimbabwe, and Mozambique while managing to displace thousands more in the southern African region.

The storm landed in Mozambique on March 15 and that country has seen the most damage so far: the coastal city of Beira has been almost completely wiped out and an inland ocean has formed that measures 80 miles long and 15 miles wide.

Massive amounts of rain caused major flooding and parts of Mozambique saw floods of up to 19 feet deep. An estimated 2 million people have been affected by Cyclone Idai, which the United Nations called “one of the worst weather-related disasters ever to hit the southern hemisphere”.

As more rainfall is expected in Mozambique and Zimbabwe, rescue workers worry that sending aid to survivors and rescuing those in need will become increasingly more difficult.

“We are looking at a severe humanitarian emergency here that is affecting thousands and thousands of people. It’s so much more severe than we were expecting,” said International Federation of Red Cross and Red Crescent Societies spokesperson Caroline Haga in an interview. “These people are now trapped in trees and on rooftops of buildings.”