Fire investigation officers have said they cannot enter what remains of the Londesborough Hotel to start their work.
Police said this morning that they were treating Wednesday's blaze as arson, but Humberside Fire and Rescue Service has warned it could be 'a few days' until the cause is known.
The building in West Street is still not secure and senior fire officers are awaiting for engineers to declare it safe for them to enter so they can try to find out where the fire began.
Emergency services were called at 1.36pm on Wednesday after reports of a fire in the upper floors of the hotel.
This was the scene on West Street 24 hours after the fire started.
At its height during mid-afternoon, there were six engines and two aerial ladder platforms tackling the fire. The fire brigade's Command Unit was brought from Brough to provide a central point for officers to co-ordinate their response.
There were two engines from Bridlington, two from Driffield, one from Market Weighton and one from Beverley, plus the crews and platforms from Scarborough and Brough.
Around 40 firefighters attended the incidents, alongside police officers who closed roads around the hotel and Yorkshire Ambulance Service paramedics, who stood by in case of any casualties.
The officer in charge Dave Bristow said: 'We were concerned about the spread to adjacent properties, the fire was well developed in the roof area and was significant.
"The roof and upper floors were completely destroyed, but we had a lot of resource here very quickly and tackled the fire without compromising the safety of our firefighters or local residents."
Crews tackled the fire throughout the afternoon and and were still damping down at midnight. Bridlington crews returned every few hours to check for 'hot spots' or reignition sources, and they returned at 3am on Friday because of worries about smoke and they used a hose reel dampen down the area.
It had been hoped that police and fire investigation officers would be able to start their work within 24 hours but the dangerous nature of the building meant that was not possible.
"It may be a few days until the cause and origin are known," said a statement.