@quantian1 correctly determined that this was an ammonium nitrate blast by analyzing the footage: twitter.com/quantian1/status/1290695231… CHEMISTRY FACT: Explosives have characteristic "detonation velocities" at which shockwaves expand. Smartphone video records at 30 FPS, so the adjacent frames here suggest the front expands at ~100 m/(1/30 sec), or 3,000 m/sec. Consistent with ammonium nitrate, not black powder. This was confirmed a few hours later: twitter.com/BBCBreaking/status/12907585… Lebanese president blames 2,750 tonnes of ammonium nitrate left in warehouse unchecked for six years for devastating Beirut blast EDIT: By the way, one of my friends was almost killed by the explosion. Thankfully they're ok. But they said: twitter.com/cyrilzakka/status/129076621… This was terrifying to experience. Hospitals are being overrun with injured people. We need blood donations and disaster relief. Help however you can. As a US citizen, is there any way I can help directly? Is there any organization that ships blood donations directly to a disaster site? I suppose that would be very difficult, so the answer is probably no; it's frustrating not being able to assist.

This video is the one that made me gasp the hardest: twitter.com/FadyRoumieh/status/12906707… Something about the distance and the fact that it's on water puts everything into stark relief.

an expert's thread from this morning: twitter.com/johnismay/status/1290858204…

I agree with your sentiment. There are videos that appear to depict the main explosion resulting from a missile strike, the folk filming react to it as it enters the frame immediately prior to detonation. It's wrong to classify something false with certainty when it is just conjecture and likely of a political nature at that. twitter.com/imranarainppp/status/129072…...

The media doesn't seem to understand how big this is yet in short and long term damage and loss of life. I guess that doesn't matter? They are more for political bickering now? Running theory Ammonium Nitrate stored at port for many years - mobile.twitter.com/HachemYassin/status…... [Edit] Skipping the loss of grain and produce in port and the actual port in a country on the brink during a pandemic this isn't just 50 dead short term mobile.twitter.com/asharfouch/status/12…...

I'd like to know why it initially sounds like fireworks twitter.com/HeshmatAlavi/status/1290683… [camera operator probably would have died in the second blast] Is that what set it off? Or is that what ammonium nitrate sounds like burning?

I am seeing other analyses that put the size of the explosion at about one tenth of this size. The analysis in this Twitter thread correlates the observed degree of damage with the distance from the explosion. It comes up with an estimated 240 tons TNT-equivalent, though naturally this comes with a considerable margin of error. twitter.com/GeorgeWHerbert/status/12907…... This Twitter thread is making the point that the explosiveness of ammonium nitrate can vary significantly depending on how it is stored. 2750 tons of AN at 20% efficiency gives 550 tons TNT. twitter.com/ArmsControlWonk/status/1290…... This range is also apparently consistent with the explosion registering as a 3.5 seismic magnitude. twitter.com/ArmsControlWonk/status/1290…... There are still a great many unknowns, and none of this should be mistaken for the real analysis which will come later, but these disparate sources of information all seem to agree with each other, to a first approximation.

There was also fireworks going of just before the blast. Storing 2750 tons of AN next to a fireworks cache seems cartoonishly stupid. twitter.com/ConflictsW/status/129068190…...

Thanks. I did check and it was quickly geo-located - twitter.com/N_Waters89/status/129068827…

Dr Moudhy Al-Rashid has a thread of ways you can help. twitter.com/Moudhy/status/1290969922672…

mobile.twitter.com/johnismay/status/129…... think this is what you meant