CHICAGO (AP) — A National Weather Service meteorologist says the agency plans to survey storm damage Tuesday in four northern Illinois counties after forecasters confirmed that at least six tornadoes had touched down there Monday.

Meteorologist Rafal Ogorek says that based on video, photos and storm reports provided by storm spotters and storm chasers, the agency has confirmed that six tornadoes caused damage in Ogle, DeKalb, and Kane Counties and Lee counties.

He says additional tornadoes likely touched down in the region, but weather service staff won’t know until they survey storm damage that appears largely confined to tree and crop damage, along with some damage to barns and other structures.