In all 2,550 homes and 173 businesses were affected, according to the initial survey.

“Our community was devastated by this storm, and our preliminary assessment shows the extent of the damage,” said Montgomery County Commission President Debbie Lieberman.

Harrison Twp. sustained the worst damage with 84 homes destroyed, including 34 in Northridge. Another 134 had major damage, according to the survey. The township also lost 34 businesses with another 19 heavily damaged, far more than any other area affected.

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The assessment team made only visual inspections from streets and did not enter structures. Further assessments will continue to refine and modify this information to be more accurate. The data include only structures and do not indicate how many housing units may be within a given building or apartment complex, so the number of people affected will be much higher than the total homes listed.

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In Dayton, 39 homes were destroyed, including 33 in Old North Dayton, and 95 more sustained major damage. Brookville also recorded 39 homes destroyed and another 42 too damaged to live in. The preliminary count in Trotwood showed 33 homes destroyed and another 98 unlivable.

The Federal Emergency Management Agency (FEMA) will survey the damage beginning Wednesday to determine whether future assistance can be given to property owners who are uninsured or under-insured as well as renters who lost belongings, a spokesman said Monday.

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People with uninsured damages from last week’s tornadoes in Montgomery County should call the county EMA’s hotline at 937-225-6217 as part of the damage assessment. The hotline is open from 9 a.m. to 6 p.m.

Dayton Mayor Nan Whaley said city officials hope to meet with representatives of FEMA. She advised residents whose homes were affected by the storms to have their addresses registered with the American Red Cross, who will be expected to pass that registry on to FEMA.

“Check in, tell them where you live,” Whaley said.

About 40 members of Ohio Task Force 1 and another 60 from regional strike teams from Cincinnati and Columbus were the first to categorize the destruction door-to-door when searching for survivors.

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The National Weather Service confirmed that 15 tornadoes touched down on Memorial Day evening and into the next day. One beginning at 10:41 p.m. traveled 19 miles from west of Brookville through Trotwood, Harrison Twp., Dayton and Riverside. It was later upgraded to an EF-4 tornado with estimated winds up to 170 mph.

More than 1,600 customers — many in the hardest-hit areas — remained without electricity Monday more than week after the tornadoes initially left 70,000 in the dark.