A line of strong thunderstorms that damaged buildings and disrupted power service across northwestern Arkansas on Wednesday was expected to continue to race across the South, bringing gusty winds and possible tornadoes, the National Weather Service said.

A tornado may have struck the Springdale area in northwest Arkansas about 4 a.m. Wednesday, according to Joe Sellers, a meteorologist with the National Weather Service in Tulsa, Okla., which oversees five counties in Arkansas.

“We are pretty certain that one occurred,” Mr. Sellers said in a phone interview. He added that a survey team was headed to Springdale to assess the damage and confirm the tornado.

Seven people were taken to area hospitals, including two people who were in critical condition, Mayor Doug Sprouse of Springdale said in a statement.

While he was thankful that there were no reported fatalities, he said that “many residents have been displaced from their homes, and numerous businesses have reported significant damages.”

Roads were closed and there were reports of downed trees and power lines, according to the Springdale Police Department. Footage from local news outlets showed roofs peeled off homes and businesses.

The Springdale School District closed schools on Wednesday because of the severe weather and power outages. The district reported significant damage to George Elementary School, in Springdale.

“The gymnasium was destroyed and the kitchen and cafeteria were severely damaged,” the school district said on Facebook.

As the storm system moved across Arkansas, the Weather Service in Little Rock issued a tornado watch for parts of the state, along with portions of Louisiana, Mississippi, Missouri and Tennessee, until 8 p.m. Central time Wednesday, noting that several tornadoes were likely.

The Weather Service warned of wind gusts of up to 80 miles per hour and said that hail as large as a quarter was possible in those areas.

The bad weather caused widespread power outages throughout Arkansas on Wednesday. More than 10,000 customers were without power on Wednesday afternoon according to PowerOutage.US, a website that aggregates data from utilities. The Arkansas Division of Emergency Managements said that Verizon was reporting 40-60 sites down which were disrupting service.

The storms came after a tornado in the New Orleans area killed at least one person last week and caused heavy damage and power outages. And earlier this month, a tornado was blamed for at least one death in Texas, where a system left a trail of destruction as it moved over areas of the Deep South.