BROOKVILLE, Ohio (AP) — A rapid-fire line of apparent tornadoes tore across Indiana and Ohio overnight, packed so closely together that one crossed the path carved by another.

The storms strew debris so thick that at one point, highway crews had to use snowplows to clear an interstate.

At least half a dozen communities from eastern Indiana through central Ohio suffered damage, according to the National Weather Service, though authorities working through the night had reported no fatalities as of early Tuesday. Some 5 million people were without power early Tuesday in Ohio alone.

The response would require a “multi-day restoration effort,” utility Dayton Power & Light said in an early morning tweet. The company said 64,000 of its customers alone were without power.

The city of Dayton urged residents to conserve water after the storms cut power to water plants and pump stations. Multiple schools in the area were closed or had delayed starts Tuesday.

Towns just outside Dayton, Ohio, took some of the heaviest hits. The National Weather Service tweeted Monday night that a “large and dangerous tornado” hit near Trotwood, Ohio, 8 miles northwest of Dayton. Several apartment buildings were damaged or destroyed.

A tornado ripped through the #Dayton metro area last night, causing damage and widespread power outages. A power flash at 0:03 seconds reveals the tornado. #ohwx pic.twitter.com/MxzEty4yFy — WeatherNation (@WeatherNation) May 28, 2019

Frightening video of aftermath of tornado in Dayton sent to us by a viewer. She says it’s off Troy Street. Many viewers have said the damage looks like a war zone… @ABC22FOX45 #daytontornado pic.twitter.com/X8fjz8Pk47 — Adam Aaro (@AdamFox45Now) May 28, 2019

It looks like a war zone. At the intersection of Crosswell and June Place in Brookville. @whiotv pic.twitter.com/o2GRflppzj — Kayla Courvell (@KCourvellWHIO) May 28, 2019

Photos taken by ODOT workers show a view from one of the department's snow plows as crews on Interstate 75 north of Dayton work to clean debris from the highway after a tornado hit the area late Monday. Photo: ODOT pic.twitter.com/meQwINAIEu — clevelanddotcom (@clevelanddotcom) May 28, 2019

A closer look at some of the damage done to the River’s Edge Apartments in Harrison Township. pic.twitter.com/Ci0B9aTSge — Allen Henry (@AllenHenry) May 28, 2019

DAYTON TORNADOES: The pictures and videos coming in from the Dayton area are so heartbreaking. The Montgomery Co. Sheriff's Dept. says several injuries have been reported. Stay tuned to #GMCle for the latest. Pics: @JakeWCPO pic.twitter.com/TYsiIdYtBg — Meg Shaw (@MegDShaw) May 28, 2019

Tornado damage at River's Edge Apartment complex on the north side of Dayton, Ohio. 📸-@MichaelTope pic.twitter.com/wGbwlEvwty — Peter Hall (@PeteWeatherBeat) May 28, 2019

#Beavercreek : You’re looking at a home on Rosehill Drive. The family was in the basement. @whiotv pic.twitter.com/n3ZrmXv1Pj — Gabrielle Enright (@GEnrightWHIO) May 28, 2019

So many law enforcement cruisers and city workers throughout Dayton right now. There are gas leaks in Beavercreek and roads closed due to fallen power lines. These are photos of a Marathon gas station in Harrison Township @FOX19 pic.twitter.com/usWToRyAEN — Maytal Levi (@MaytalLeviWXIX) May 28, 2019

Brookville, Ohio with BIG damage near the high school there (just west of Dayton)

📸 – @FOX19Catherine pic.twitter.com/q7JzcULUew — Peter Hall (@PeteWeatherBeat) May 28, 2019

DAYTON TORNADOES: These are the front doors of Brookville High School, as shown on @whiotv earlier – the roof has also been blown off #ohwx pic.twitter.com/Pv1BgTqDOz — Evan Millward (@EvanMillward) May 28, 2019

Sunrise shows just how bad the damage is here in Dayton. An entire strip mall in Northridge is gone. @Local12 @ABC22FOX45 pic.twitter.com/m5JI52QNjz — WalterSmith-Randolph (@WalterReports) May 28, 2019

Crystal Miller standing in awe of the damage. @ABC22FOX45 pic.twitter.com/oU5fgmvslB — Allen Henry (@AllenHenry) May 28, 2019

Tune into @FoxFriendsFirst at around 6:35AM. I’ll be live talking about the powerful storm and the damage just outside of the Dayton area. @FOX19 pic.twitter.com/Ekiadyqzy1 — Catherine Bodak (@FOX19Catherine) May 28, 2019

Such a mess — roof collapsed on 2 cars. 8 miles outside of Dayton near Brookville High School @FOX19 pic.twitter.com/fG9R6nboAg — Catherine Bodak (@FOX19Catherine) May 28, 2019

This aerial photo shows tornado damage at the Westbrooke Village Apartment complex in Trotwood, Ohio, after tornadoes ripped through the Dayton area and neighboring state Indiana late Monday night. Photo: The Columbus Dispatch via AP pic.twitter.com/TNXQvR9q1Y — clevelanddotcom (@clevelanddotcom) May 28, 2019

More homes with damage in Dayton… one is missing a roof. There are snapped trees everywhere. pic.twitter.com/9O44xY6vyi — 10TV.com (@10TV) May 28, 2019

A large and destructive storm ripped through the Dayton area. This is just about 8 miles away from downtown north and west. @FOX19 pic.twitter.com/sb28VNHsPT — Catherine Bodak (@FOX19Catherine) May 28, 2019

Brand new drone and daytime video from @CNN shows the devastation left in Ohio after tornadoes rip through the state. You can see just how severe the damage is this morning in the Dayton and Celina areas. @koat7news pic.twitter.com/0Iep30dS1l — Sasha Lenninger (@SashaKOAT) May 28, 2019

Apartments off of Shoup Mill Road received heavy damage in Dayton tornado.@Enquirer pic.twitter.com/NCowAGwMvM — Albert Cesare (@AlbertCesare) May 28, 2019

🚨 New video this morning showing the damage from Monday's tornadoes in western Ohio. This is Harrison Township near Dayton. The Buckeye State could see more tornadoes today so keep checking with @WeatherNation for the latest severe updates. #Weather #Tornado #Ohio #OHWX pic.twitter.com/MqTP8mRUsc — WeatherNation (@WeatherNation) May 28, 2019

Just before midnight, not 40 minutes after that tornado cut through, the weather service tweeted that another one was traversing its path, churning up debris densely enough to be seen on radar.

The aftermath left some lanes of Interstate 75 blocked north of Dayton. Trucks with plows were scraping tree branches and rubble to the side to get the major north-south route reopened, according to Matt Bruning, a spokesman for the Ohio Department of Transportation.

Trying to clear the debris in the middle of the night is a difficult task, complicated by darkness and downed power lines, Bruning said.

“We’ll do a more thorough cleaning after we get lanes opened,” he told The Associated Press by text early Tuesday, noting that tow trucks would have to haul off damaged vehicles along the roadway, too.

In Brookville, west of Dayton, the storm tore roofs off schools, destroyed a barn and heavily damaged houses.

Crews were also clearing debris in two other counties northwest of Dayton.

In Montgomery County, which includes Dayton, Sheriff Rob Streck said many roads were impassable. The Montgomery County sheriff’s office initially said the Northridge High School gymnasium would serve as an emergency shelter in Dayton but later said it wasn’t useable.

In Indiana, at least 75 homes were damaged in Pendleton and the nearby community of Huntsville, said Madison County Emergency Management spokesman Todd Harmeson. No serious injuries were reported in the area or other parts of the state.

Madison County authorities said roads in Pendleton, about 35 miles northeast of Indianapolis, are blocked with trees, downed power lines, and utility poles. Pendleton High School is open as a shelter.

The National Weather Service said a survey team will investigate damage in Madison County and possibly in Henry County. Another team may survey damage in Tippecanoe County.