Rescue officials said two additional people were found dead Tuesday afternoon in a 2-mile-long debris field left by the most destructive natural disaster in recorded Putnam County history.

Eighteen people in total, including several children, were confirmed killed in a violent, rapid tornado that swept through an area west of Cookeville early Tuesday, officials said.

More than 250 rescue workers scoured the streets and subdivisions so devastated by the twister Tuesday that homes and businesses are unrecognizable.

More:Officials identify 18 killed in Putnam County after violent tornado

"This is on a level unlike anything most have ever seen," Cookeville Mayor Ricky Shelton said. "We 110% have been trying to reassure the community, get resources where they need to be, and establish what's necessary to take care of families."

Eighty-eight people were taken to Cookeville Regional Medical Center, including some in critical condition. Another 77 people have been reported missing, but authorities believe some may be unreachable due to ongoing power outages.

More:Rescue officials update list of missing in Putnam County tornado search

"We have been able to go door to door on all standing structures that are not demolished," Putnam County Sheriff Eddie Farris said. "That is well over 100 structures, closer to 150."

Rescue workers searched 60% of the impacted area just west of Cookeville on Tuesday and planned to work through the night.

They are particularly concerned about a marshy 20-acre field strewn with debris in the tornado path, between North McBroom Chapel and Echo Valley Estates.

"If there are more victims, it's a high probability that's where we would find them," Farris said.

Family members looking for their unaccounted loved ones are asked to go to Church on the Hill off Highway 111 North. Emergency responders are still working to identify the victims with the help of family members there, at 3001 Phillips Cemetery Road.

“This is an absolutely tragic and devastating day for our city and county,” Shelton said. “Our first ask is for prayers for our families, community and responders that are out there and have been out there almost 10 hours searching and rescuing and working through that.”

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National Weather Service officials will arrive Wednesday to determine the scale and intensity of the cyclone that lasted for only about 10 minutes.

Debris was blown up to four miles away, and major water and gas lines were ruptured. But no injuries were caused by the utility outages.

Alison Cobble and Daniel Whitson were sleeping when they heard the tornado sirens. Then the storm outside grew eerily calm and the power went out.

"The train noise came and we went into the bathtub," Whitson said. "Then it sounded like the building was coming down."

The windows were blown off their house and car, and water poured in through the ceiling fan and open windows.

"I was shaking," Cobble said. "We just told each other we loved each other and all that stuff."

The couple packed up the belongings they could salvage in a pickup later Tuesday morning and planned to stay with a family member. Their entire subdivision was in shambles.

Gov. Bill Lee flew out Tuesday and President Donald Trump is expected to arrive at the hardest hit area in the storm later this week. Officials declared a state of emergency for Putnam County and the city of Cookeville to mobilize state and federal aid.

“This tornado absolutely demolished and devastated everything in its path," Farris said. "It's a major scene down there right now. In a lot of cases, as we move something, something else falls so we're trying to be careful as we go."

Sixteen victims were discovered during the recovery effort in the morning and two more were found in the afternoon, officials said. Tornado warnings went out over sirens and cell phones, but the storm took many by surprise.

"There were some children, I'm sorry to say," Putnam County Mayor Randy Porter said. "We are still working to find out ages. It hit so fast, most of these folks were sleeping."

They have asked the public to stay away from the affected area to allow emergency responders to work.

"This is going to be a multiple day event and we're going to need resources, food and so forth for the next several days," Porter said. "Please contact us before you bring things so we can coordinate."

Down the road from the subdivision where Cobble and Whitson lived, Mike Williams surveyed the rubble that was left of his Williams Auto Sales shop.

"I was shocked when I got here and saw what it had done," Williams said. "I keep coming across things that just don't look like it's possible. Our refrigerator was at that service station down there about a half mile away.

"But this can be fixed. We lost one of my son's friends."

The hardest hit areas are Charleston Square, Plunk Whitson Road, Echo Valley, Prosperity Point, North McBroom Chapel and Double Springs Utility District.

An emergency shelters is at Cookeville First Baptist Church, 18 S. Walnut Ave. But most displaced people sheltered at homes of relatives and hotels.

How to help

To donate blood, visit Blood Assurance, 155 W Broad St. or the Cookeville Regional Medical Center, 1 Medical Center Blvd., both in Cookeville.

Those seeking to volunteer should coordinate with the rescue team by emailing HelpNow@PutnamCountyTN.gov. The account is averaging seven emails per minute so responses are delayed, officials said Wednesday.

Financial donations to the victims' families can be made directly to the Cookeville Putnam County Tornado Relief Fund at Bank of Putnam County locations.

To report a missing or found person, call 931-646-4636.

To donate supplies such as water, diapers, clothing and nonperishable foods call 931-526-8015.

To provide meals for rescue workers, call 615-585-6341.

Sandy Mazza can be reached via email at smazza@tennessean.com, by calling 615-726-5962, or on Twitter @SandyMazza.