The patrol unit he was driving rear-ended an Oncor bucket truck stopped at a red light at U.S. 67 and Texas 174 around midnight, Sheriff Bob Alford said. The cause of the crash remains unclear.
"The nurses have told me it will take time, but he will heal," Alford said.
The operator and passenger of the utility truck, described by Alford as a 5-ton vehicle, were treated for minor injuries. The truck was essentially unharmed, Alford said.
Nowell has a litany of injuries, according to Alford. He has six broken ribs, a broken leg, possibly a broken vertebrae, neck injuries and a deep laceration on his head.
"They've put him into a medically induced coma to help him rest," Alford said.
The crash totaled the deputy's patrol car, Alford said.
"He was trapped in the car and we're just lucky he's alive," Alford said. "Our thoughts and prayers go out to Deputy Nowell and his family."
Tuesday, Alford and Chisholm Trail 100 Club President Bruce Basden were among Nowell's visitors in the hospital.
"With his broken ribs, the nurses tell us an area of danger would be if he were to get pneumonia or something like that," Alford said.
Nowell has been a deputy in the sheriff's office for 15 years, being named a past Deputy of the Year and receiving other awards and commendations. He's eligible to become the next sergeant in the department.
"Its all speculation at this point what might have happened," Alford said. "He could have fallen asleep, become distracted or maybe have had a seizure."
Nowell's cell phone records indicate he had not sent a text within an hour prior to the crash.
"We're just thankful we still have him," Alford said. "A lot of the deputies, especially those who responded to the crash, have been very distraught. It's a very emotional time for us."