An American firefighter has explained the specific challenges faced by the Parisian fire brigade in tackling the enormous blaze that ripped through the centuries-old Notre Dame cathedral in Paris last night.
The fire was brought under control late on Monday after it had consumed the structure's iconic spire and much of the roof, leaving millions - including the U.S. President - wondering how it could have spread so quickly.
According to former St Louis firefighter Gregg Favre, the fire brigade's efforts would have been hampered by limited access to the building, as well as the age and design of the almost 900-year-old structure.
A major fire broke out at the landmark Notre-Dame Cathedral in central Paris on Monday sending flames and huge clouds of grey smoke billowing into the sky
Firefighters battled for hours to halt not only the immediate danger to life but also to preserve the cathedral and the priceless treasures it houses.
As the world watched the horrifying incident unfold, President Donald Trump tweeted from aboard Air Force One to suggest the use of flying water tankers to douse the flames.
Addressing a crowd at his Tax Day event in Missouri later that day, Trump expressed his astonishment that the fire was 'burning at a level that you rarely see a fire burn.'
In a thinly-veiled rebuke to the President, France’s civil defense agency tweeted that that: 'All means are being used, except for water-bombing aircrafts, which, if used, could lead to the collapse of the entire structure of the cathedral.'
President Trump suggested the use of airborne tankers as he tweeted about the fire en route to Missouri from Air Force One
Sécurité Civile appeared to slam President Trump's suggestion, by explaining - in its only English-language tweet on the Notre Dame disaster - why using water-bombing aircrafts were not used to tackle the blaze
After seeing videos of the blaze on social media, Favre - who is a former director of Missouri Department of Public Safety - attempted to explain some of the more technical aspects of the preservation effort, as well the professional procedure that the fire brigade would have had to follow.
'The first issue is how old churches are built, heavy timber construction with large open spaces and very few (if any in a church like Notre Dame) fire stops,' he wrote on Monday evening.
A firestop a form of passive fire protection used to seal openings and joints in a wall or floor, and impede the spread of fire in modern buildings. Construction on Notre began in 1163.
With structure as tall as the Notre Dame peak, normal methods of stemming the spread of the fire are all-but impossible.
Gregg Favre, a former firefighter and director of Missouri Department of Public Safety, tweeted on Monday evening some of his professional observations about the fire and why it could not be immediately stopped
'In firefighting there is something called a "trenchcut" that basically opens a large roof up from peak to gutter, allowing space to stop fire spread,' Favre wrote.
'Given the peak of the cathedral roof and advanced fire conditions, this is an unlikely option in the main area of the building.
'Even if aerial waterways (think hook and ladders with prepiped hoses) could reach the roofline, it is difficult to see how they would get an angle that would get water on the fire - its just too high.
'So this means you have to put firefighters inside... a whole other problem. The primary option is large 2.5" fire hoses.
Favre did not mention President Trump in his tweets, but his post came hours after Trump suggested using water-bombing aircraft to tackle the flames - which French security officials later said could have destroyed the entire centuries-old structure
'These are heavy, difficult to maneuver and against a fire like this, largely ineffective.
Favre added that firefighters would be reluctant to use this option, as it means