CEDAR RAPIDS, Iowa (CNN) -- The worst flooding in 15 years has paralyzed large sections of eastern Iowa, with heavy rains and brutal storms leaving their marks from one end of the state to the other.
"We are working around the clock with all of the county emergency management operations," Iowa Gov. Chet Culver said late Thursday.
Culver added Muscatine County to an emergency disaster proclamation that he issued earlier. Fifty-five of the state's 99 counties are now under the designation.
Rising flood waters forced evacuations in Cedar Rapids on Thursday, displacing thousands of people. Watch flooding escalate within hours »
Mercy Medical Center, a hospital in Cedar Rapids, began evacuating its 176 patients.
"Our hope was to continue to operate and serve our patients as we always have," said Tim Charles, president and CEO of the hospital. "Unfortunately, this has become a disaster of unpredictable and potentially catastrophic proportions."
The flooding is snarling major roadways across the state. The Iowa Department of Transportation lists more than 35 state and federal highways that are closed or blocked, including a section of I-80 east of Iowa City.
The state is focusing on providing food, water and shelter to the evacuees, Culver said.
In addition to the flooding, Iowa has been wracked by series of deadly tornadoes since late May. At least 10 people have died, including four Boy Scouts after a twister hit their camp in western Iowa Wednesday.
"It's certainly been a real blow," Culver said of the natural disasters. "Despite the setbacks and challenges at hand we will get stronger as a state."