The geological event that then occurred is known today as a pyroclastic flow, a phenomenon that had never been scientifically observed. Pyroclastic flows are a fluidised mix of rock fragments and hot and highly toxic gasses entrapped in a thick and turbulent ash cloud. These often result, as occurred on Mont Pelée, from a collapse of the lava cone. Pyroclastic flows, which spread laterally, can travel as fast as 100km/h and generate temperatures up to 700 degrees Celsius, hot enough to cause surrounding bodies of water to boil. The super-heated elements of a pyroclastic flow may ignite within the ash cloud causing the inside to glow a fiery red or orange. This process was observed at Mont Pelée by the French geologist Alfred Lacroix, who subsequently coined the term ‘nuée ardente’, or ‘glowing clouds’. Pyroclastic flows constitute the most dangerous form of volcanic event, obliterating almost everything in their path and causing swift, often instantaneous death.
The effects of the eruption on land are not the focus of this paper, but it is evidenced that within but a few minutes up to 30,000 of St Pierre’s refugee-swelled population were either dead or dying. The author Alwyn Scarth renders a graphic summary of what took place inside those two minutes in his book La Catastrophe:
Those inside buildings had virtually no warning that they were about to die. They heard the noise of the advancing nuée ardente reach a sudden deafening crescendo. The roofs ripped off, the walls collapsed, then the scalding blast killed them before it could even set their clothes alight. The scorching fumes, ash and gas seared their skin and burned into their throats and lungs as they struggled to flee, or even just to breathe. They had to inhale the hot dust and ash in a desperate effort to stay alive. And they died as their throats and lungs burned out, their tongues swelled up to twice normal size, and blood gushed from their mouths. Then the dust coated their bodies.[3]
Ludgar Sylbaris, a labourer incarcerated the previous evening in St Pierre’s thick-walled and sturdy jail cell, was one of the only survivors found amid the ruins of the town.
Although those mariners and visitors staying offshore had a greater chance of survival, there were more ways for them to die. Those seaman and passengers caught exposed above deck were either burned or scolded to death, or hurled into a surging, broiling sea. Those in the wheelhouse or other semi-exposed areas above deck faced asphyxiation from the choking ash cloud. Those on the lower decks avoided the worst of the heat and ash, but were most likely to drown as their ships capsized or broke up. In some cases, a porthole, left open or closed, would be the difference between life and death.
The only eyewitnesses to the nuée ardente were those mariners attending to tasks on deck. Aboard the Roddam, Captain Edward William Freeman was welcoming the supercargo on deck when he heard ‘a sudden roar that shook the earth and the sea’. The Roraima’s first mate recalled that ‘the atmosphere seemed to shudder’. It was, he said, ‘as if all the dynamite in the universe had blown up the mountain’. According to assistant purser Thompson: ‘There was a tremendous explosion… soon after we got in [to port]. There was no warning. The side of the volcano was ripped out and there was hurled towards us a solid wall of flame.’ Out at sea, Emile Bertin saw through his field glasses that ‘the whole coast was lit up’ and ‘the mountainside was red, as if it had melted.’
Captain Freeman told reporters what happened as the nuée ardente reached the Roddam:
A burning mass thrown up by the volcano struck my steamer broadside on. The shock was so terrible that it nearly capsized the vessel, big as she is. Hearing the awful explosion that had preceded the shock to ourselves, and seeing what looked like a great wall of flame rapidly approaching us from the volcano, all of us sought shelter wherever it was possible to get from the terrible hail which then began to fall around us… The hot dust raked us from stem to stern, firing everything that it touched as it drove over us, swirling along in a torrential downpour, filling the ship, penetrating every crevice.
Captain Freeman was lucky. He just had time to reach the chart-room which gave him some protection from the firestorm. Captain Muggah aboard the Roraima was less fortunate. ‘He was facing the fire cloud with both hands gripped hard to the bridge rail, his legs apart and his knees braced back stiff’, remembered Scott. ‘In another instant it was all over for him. As I was looking at him he was all ablaze.’ Thompson reported seeing Muggah as ‘he fell unconscious from the bridge and fell overboard’.
Behind the ‘great wall of flame’ of the pyroclastic flow rose a tsunami so powerful as to cause ships’ hulls to repeatedly strike the sea bottom. The Roddam was ‘struck as if by a giant hand’, recorded Freeman. ‘The tidal wave picked up the ship like a canoe and then smashed her’, remembered Thompson. ‘The sea was torn into huge whirlpools, wrote Scott. ‘One of these whirlpools swung under the Roraima and pulled her down on her beam ends with the suction.’ Clara King described the impact of the eruption below deck on the Roraima:
I was dressing the children for breakfast when the steward… rushed past shouting “the volcano is coming!” We closed the door and at the same moment came a terrible explosion which nearly burst the eardrums. The vessel was lifted high into the air and then seemed to be sinking down. We were all thrown off our feet by the shock and huddled crouching in one corner of the cabin.
The forces that had ‘nearly capsized’ the Roddam would sink all of the smaller vessels moored around her. The end of the Grappler, anchored closest to shore, was witnessed by Purser Thompson: ‘The wave of fire was on and over us like a lightning flash. It was like a hurricane of fire. I saw it strike the cable steamship Grappler broadside and capsize her. From end to end she burst into flames and then sank.’ The Grappler sank with all hands. Only one of Diamant’s crew of eight survived her sinking, cabin boy Jean-Baptiste Innocent unwittingly blown off the boat while he was attaching a hawser to the quay. Once in the water, Innocent had the presence of mind to dive under repeatedly to avoid the worst of the heat effects. He was forced to spend seven hours clinging to flotsam before being rescued. So too were three Italian seamen thrown overboard from the Nord America. At the other end of the bay, Teresa Lo Vico had her masts ‘scythed down’ by the nuée ardente, one of them falling on and killing Captain Ferrara. Ship’s engineer Jean-Louis Prudent was one of several mariners who later claimed they owed their survival to having fallen under the bodies of dying shipmates. Emerging from this pile of corpses relatively unhurt, the resourceful Prudent managed to retrieve a small boat in which he and other survivors, including his own wife and Captain Ferrara’s widow, were eventually able to reach a safe haven.
Bow Creek to Anatahan 