Integrated Regional Information Networks reported the Category 4 storm came ashore south of Toamasina and then moved inland toward the capital, Antananarivo. While Giovanna had weakened by the time it reached the capital, its winds were still clocked at 112 mph, IRIN said.
Trees were uprooted, many houses were damaged or destroyed, infrastructure was damaged, water supplies were disrupted, and flooding and landslides were reported, IRIN said.
The initial death toll stood at 10, the National Disaster Risk Management Agency said.
The aid organization Care International, the disaster relief office of the U.S. Embassy, the faith-based Medair and the U.N. Children's Agency had begun the task of assessing the damage and people's needs, IRIN said.
"From the east coast we have received reports of damage and human loss caused by heavy winds and flooding," Dominic Stolarow, UNICEF emergency coordinator in Madagascar, said in a statement Tuesday.
John Uniack, Care International director for the country, told IRIN a helicopter team estimated 70 percent of the dwellings in Brickaville and 60 percent of the structures in Vatomandry were destroyed or damaged to the point of being uninhabitable.
The two cities have a combined population of about 400,000.
"The populations will definitely require government and international assistance to get back on their feet and we will have a better sense of this in coming days," Davis said. "Our initial impressions are that Cyclone Giovanna damage doesn't cover a vast area, but some areas are quite hard hit, especially the districts of Brickaville and Vatomandry."