Mr Drohan, from Harrow, north west London, died after his car was struck at the eastern end of the bridge over the River Colne on Lower High Street in Watford shortly before 7am.
He was among four people to die as a result of the heavy winds and rain that lashed southern England. The other dead were a 17-year-old girl crushed in a mobile home by a tree and two people who died in a gas explosion triggered by a falling tree.
A 14-year-old boy who was swept out to sea is feared dead after the coast guard called off the search off the coast of East Sussex.
Mr Drohan’s family said: "He was the best husband and father anyone could wish for. You couldn't find anyone who had a bad word to say about him.
"He was very supportive to everybody who knew him and couldn't say no to helping out with anything.
"He was an active member of the community who was involved with local groups and had recently helped Team Harrow of The Challenge Network helping to shape the lives of hundreds of young people within the local community."
A police officer at the scene of the incident said that a millisecond's difference in Mr Drohan's journey would have made for "a different story".
The unnamed officer said: "This is a major artery into Watford and we were lucky it was school half-term. If it wasn't, we'd have had a lot more traffic coming through here."
The jagged stump of the tree, about three feet across and broken 12 feet up, could be seen in the greenery at the side of the road.
Investigators examined the site to rule out foul play before the main part of the tree trunk was lifted off the car with a mobile crane and loaded on to a container truck. The rest of the tree was fed into a shredder lorry.
Mr Drohan was a long-serving local authority employee and had recently taken up golf.
Susan Hall, leader of Harrow Council, said: "This is an absolute tragedy and everyone is devastated. Donal was one of our public realm managers and had worked for us for nearly 25 years.
"He was always cheerful, and passionate about his job keeping our streets clean. His council colleagues are finding this very hard to deal with. Our thoughts are with Donal's family both here and in Ireland."
Richard Searle, director of Quality Lounge Suites in Watford, said the incident was "very upsetting" and he was "very sorry" for the man's family.
He said: "It happened about a minute before I got here. I was driving to work - normally I try to get in early - and as I got here, the traffic had slowed down. I couldn't go straight in, so I pulled on the drive, parked my car up, and then I walked down the road assuming there'd been an accident.
"I noticed as I walked down there that a tree had fallen on top of a red Peugeot. I didn't like the look of what I saw and it was too late for me to do anything. One minute earlier and it could have been me. I will say the police and ambulance were very quick to arrive."
Roger Rogero, 54, a sales consultant at HSS Hire, also arrived at work just after the accident happened at the junction near a Wickes store and a Mercedes showroom.
He said: "There was a police car just outside us, officers stationed by the telephone box, and loads of police and police cars in Wickes, opposite the Mercedes dealer. I could see four or five police cars, ambulances, and fire engines. Beyond that it was just a mess, chaos."
The car had been travelling south-eastwards - on the opposite side of the road to the tree that fell - and was towed away just before 11am, he added.