A £70m hangar has been damaged at the RAF's biggest base and an Army building has suffered serious damage as Storm Eunice batters the UK.
The Army office building is at Larkhill Camp in Wiltshire, it has been confirmed, while the hangar is at RAF Brize Norton in Oxfordshire.
Video shows parts of the hangar's roof being ripped off by the strong winds.
RAF Brize Norton said a "clean-up operation" will begin once it is safe to do so.
"We are aware that due to high winds there has been damage to one of our aircraft hangars," the base said in a statement.
"We are liaising with local authorities to ensure the appropriate actions are taken and the station has taken the decision to close Station Road as a precautionary safety measure until further notice.
"A clean-up operation will commence once the storm subsides and it is safe to do so. There is no immediate operational impact. We would advise the public to be extra vigilant or if possible avoid the area.”
Meanwhile, footage posted on social media by the Fill Your Boots page showed the damage at Larkhill, with it appearing the roof of the building had been completely blown off by the gusts.
A person can be heard in the background of one video, saying: "Literally the whole roof came off."
A second video, also shared by the Fill Your Boots Twitter account, seemed to show a large amount of debris on the ground with the individual filming the scene, saying: "So that was the roof on this building."
"Safety is our top priority," an Army Spokesperson said.
"We are aware of reports of storm damage on various MOD sites and will work to resolve them as quickly as possible."
Weather warnings have been in place for most of the UK due to the storm, including rare red weather warnings – the Met Office's highest alert, meaning danger to life is expected.
Eight hundred military personnel have been placed on higher readiness to potentially assist with the aftermath of Eunice.
Millions of people have been urged to stay at home for the day on Friday due to safety fears over the impact of Eunice, one of the worst storms to hit the UK in a generation.
A member of the public is in hospital with serious injuries after being struck by falling debris from a roof in Henley-on-Thames, Thames Valley Police said.
Tens of thousands of homes have been left without power, while flights, trains and ferry services have been suspended, and roads, schools and businesses have shut as potentially record-breaking gusts of more than 120mph have been recorded in some areas.
London Ambulance Service said two people were taken to hospital after being struck by falling debris and a tree in separate incidents in Waterloo and Streatham.