The track is next to a swollen river.
F1 said it wanted to avoid further burdening emergency services.
De Vries and Tsunoda drive for AlphaTauri, which is based in Faenza, a flooded city close to the Imola track.
Rescuers used boats to transport people through the flooded streets of Faenza on Thursday.
Dutch driver de Vries said he was trying to reach the Faenza factory on Tuesday night ahead of marketing events scheduled for Wednesday but the roads were cut off.
“Faenza is already flooded and I am unable to get to my hotel. Returning to the highway is no option either. Stuck in a little village with one fully booked hotel,” he posted on Instagram on Thursday, recounting his experience with pictures and video of roads blocked by landslips.
“Fortunately McLaren got stranded there earlier and their front jack (mechanic) Frazer was kind enough to give me his room. The following morning, the hotel lobby turned into an emergency shelter for people who were forced to escape their homes during the night.”
De Vries said he eventually made his way home via the city of Florence after an “adventurous” drive on mountain roads and offered his thanks to local people who helped him on his journey.
His teammate Tsunoda, who began living in Faenza in 2021 to work with AlphaTauri, said the city was badly hit.
“After a horrible night the town is heavily impacted: dust, mud, and the smell of gasoline everywhere,” the Japanese driver posted on social media on Wednesday.
“Currently people are struggling to find food and especially places to stay, after many have been evacuated from their own homes.”
AlphaTauri said its factory has not been affected by the floods and “everything is being done to ensure the safety of our employees and their families”.
The team and both its drivers issued appeals for donations to help people affected by the floods.
It is unlikely the Emilia-Romagna Grand Prix will be rescheduled because of the busy calendar.
Angelo Sticchi Damiani, the president of the Italian Automobile Club, which oversees all racing in the country, told the La Presse news agency a one-year extension to the contract for the race, set to expire in 2025, is the likeliest outcome.
“It’s 99% sure that it will be made up in 2026 after the contract is renewed,” Mr Sticchi Damiani said.
Ferrari, which backed the decision to cancel its home race, said on Thursday it is donating one million euros (£870 million) to flood relief efforts in the Emilia-Romagna region.
The decision to cancel the Emilia-Romagna GP was met by strong support from teams and drivers including seven-time champion Lewis Hamilton and defending champion Max Verstappen, who leads the standings from his Red Bull teammate Sergio Perez.
The next race is the Monaco GP on May 28, and the Spanish GP is a week later.