'I assumed the art school fire was a social media blip'
Like many people, I assumed it was a social media blip, a rerun of images and news from the fire at Glasgow School of Art in 2014.
But like so many people, I realised with horror, that this was a new fire, four years on from the one which devastated the east wing of the Mack, and destroyed the iconic library.
"My heart is breaking" tweeted the artist Alison Watt, beneath a picture of the blazing building.
And for so many people, whether staff or students, tourists or passers-by, that was the overwhelming sentiment.
"I hoped I'd got it wrong, and would waken it up realising it was all just a horrible dream," said Stuart Robertson, director of the Charles Rennie Mackintosh Society.
What makes the fire so cruel is that it comes in the midst of Mackintosh150, a celebration of the artist, architect and designer.
On 7 June, his actual birthday, a number of enthusiasts gathered to celebrate the launch of Mackintosh at the Willow, a £10m restoration of his iconic tearooms.
Barely a block away from the Mack, there was lots of excitement about the eventual return of this Mackintosh quarter, and the kind of impact it could have on international tourism.
And it is heartbreaking that it has happened in these final stages of restoration.
Four years has allowed a whole class of students to graduate, not just those whose work was salvaged from the Mack in 2014, and who presented a single work each in their degree show in solidarity.
It has also allowed a worldwide campaign to raise millions for restoration - with Brad Pitt and Peter Capaldi (a former student) offering their support.
And it has allowed an army of experts to start piecing together the Mack from photographs.
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Interiors have been recreated - the Mackintosh Library has been taking shape in an Edinburgh warehouse, the craftman's main concern whether the American tulip wood, as used originally, would be too shocking for a 21st century audience, used to the dark, stained interior.
I understand the interiors have yet to be installed. That was due to happen over the next few months as the last tranche of funding was announced.
It is hard to tell from aerial footage the scale of the damage but it seems to be far greater than the previous fire and it may be days before the full impact can be assessed.
I was on site in 2014, just a few days after the previous fire. I wrote:
"The rooms may smell of smoke, the hallways piled high with debris, but it's heartening to see how much of the Mackintosh and its contents survived."
"Whole rooms and their contents are left intact. The Mackintosh Room - used for board meetings - looks as if its occupants have just stepped out for a breath of air. The fireplace, light fittings, panelled bureau and distinctive windows show no trace of the devastating fire which swept through the building last Friday."
Sadly it doesn't seem as if the Mackintosh has fared so well this time.
The unscathed east elevation was every bit as consumed as the west and with it the painstaking structural repairs of the last three years - the roof, the famous "hen run", the studios and the library.
And while social media is full of tributes - like student, Anna who says the Mackintosh Library made her decide to become an architect, it is hard to see how that can translate into new funding, and the will to start again.
Glasgow School of Art has once again been inundated with messages of support and offers of help.
The first minister has also renewed the Scottish government's support - in coming days, and in the future.
Whether that is enough to allow the Mackintosh to rise again from the ashes is unknown at this stage.
Perhaps the last word should be left to Mackintosh himself - as quoted by artist Lachlan Goudie in his recent documentary for BBC Scotland, Mackintosh: Glasgow's Neglected Genius.
"You must be independent, independent, independent - don't talk so much but do more - go your own way and let your neighbour go his.
"Shake off all the props - the props tradition and authority give you - and go alone - crawl - stumble - stagger - but go alone."
Here's to the Mack staggering onwards once more.