Emergency responders said more than half of the city's streets were flooded Saturday morning.
The Grant County Emergency Management Office reported significant flash flooding in Boscobel.
Emergency Management representative Steve Braun said in a release significant flood damage to homes, basements and city infrastructure is expected.
"Significant flooding from last night's storms [has resulted in] water pooled in many areas of the city, damaging homes and businesses," Braun said.
A shelter was established at the Blaine Gym that is housing several families until water recedes, Braun said.
At 9 a.m., public safety personnel began knocking on doors to assess damage, Braun added.
Officials said the Swiftwater Rescue Team is working to evacuate elderly and special needs residents from affected homes and apartments.
By 10 a.m., Braun said some water had receded.
Power utilities were assisting residents in shutting off power to flooded homes. Emergency personnel were helping direct and control traffic to isolate affected areas and check on residents.
Braun said the Salvation Army was responding and 100 clean up kits had been requested. The Red Cross is also responding to aid workers and families.
Highways 60 and 61 were closed in Crawford County north of Boscobel due to landslides, the emergency management office said.
Up to 300 feet of railroad was washed out, according to a report.
Damage had also been reported in Woodman, Mt. Hope, Patch Grove, Blue River and surrounding rural areas as of Saturday morning, Braun said.
The Grant County Emergency Management Office advised people not to travel to Boscobel, as non-essential traffic will be restricted and many streets are closed.
Officials said Boscobel residents can report damage to city hall at 375-5001. Other areas of Grant County can call 608-723-7171 to report damage or request assistance.
Anyone in need of immediate assistance or with a life-threatening situation should call the Grant County Sheriff's Office at 608-723-2157 or 911.