She sits cross-legged on the bed, hands on her knees, lips pursed, every breath a mountain to climb. It is 6.11pm on Monday, November 21, 2016. She feels like she's suffocating. She thinks she might be about to die.

"Asthma, Code 1, time-critical," was what the emergency call dispatcher said over the radio. Lights and sirens. Now, paramedic Scott Drysdale listens to Jackie Falzon's chest, measures her oxygen saturation levels (how much oxygen her blood is carrying) – 89 per cent is bad news – and slams a nebuliser mask onto her face, delivering a combination of oxygen, Ventolin and Atrovent to dilate the airways in her lungs. Her breathing improves momentarily before crashing again.

The young mother's words wheeze out between gasping breaths. "I'm ... going ... to ... die," she says. "I … cannot … breathe ... I … know ... this … is ... my ... last ... moment." 

Drysdale, 27, grabs her hand. "I've got you," he says, trying to calm her. "Breathe with me." H

is colleague, 25-year-old Sebastian Smialy, has sprinted out to their truck on this Sunshine West street to get a wheelchair – there's no way the stretcher will fit down the narrow hallway – and to call for back-up. In a case such as this, they need a MICA (mobile intensive care ambulance) paramedic here now.

Smialy returns. He hasn't been able to get through to ESTA, the Emergency Services Telecommunications Authority that manages 000 calls. The radio traffic is nuts. Something must be happening, he says. In the bedroom, he tries the radio again. Finally, he's through. A voice tells him: 

The two young paramedics have never before attended such a critical asthma patient. Neither of them has ever administered adrenaline, the big gun in dire cases like this. They exchange a look: they're on their own. Load her up and go, that's what they've got to do.

Drysdale shoots a dart of intramuscular adrenaline into Falzon's left arm. The adrenaline should quickly relax her narrow lower airways, where muscles are contracting and in spasm and mucous membranes are swelling.

Now, the young men ask Falzon to lean on them while they manoeuvre her into the wheelchair. But the adrenaline hasn't done what they'd hoped it might. Jackie Falzon, 21, the mother of a four-month-old boy, slumps, barely conscious and dangerously ill.

Later, doctors in the emergency department (ED) of Sunshine Hospital, about 20 kilometres west of Melbourne's CBD, will say that Jackie Falzon was an early-warning sign of what lay ahead that night. Sunshine, along with Footscray Hospital, the other major facility in the city's Western Health network, will be in the eye of an unprecedented catastrophe that will leave nine people dead, throw an apocalyptic cast on chaotic hospital EDs across the city, become the subject of three official inquiries, and propel an obscure and little-studied medical condition – thunderstorm asthma – into headlines around the world.

They were the first Melbourne hospitals to feel the brunt of a line of storm cells that swept in from western pasture lands carrying a load of allergenic ryegrass pollen, and took about one third of the 30 patients across the two cities admitted to intensive care with life-threatening respiratory reactions to the pollen.

Across the board, the numbers are staggering: through Monday night and into Tuesday, nearly 10,000 people with respiratory distress, many of whom had never before suffered asthma, attended EDs and community health facilities in Melbourne and Geelong; 575 people were admitted. Between 6.30pm and midnight, 132 ambulances arrived at Footscray Hospital (normally it sees 40 ambulances in a 24-hour period). Over the two-day period of the asthma crisis, Western Health EDs saw more than 1200 patients – about three times more than normal.

Just before 7pm, Ambulance Victoria's executive director of emergency operations, Mick Stephenson, took a call from his Metropolitan West director to say there were no vehicles left to dispatch in the west, even for the most critical of cases. By 8pm, across the city, there were 150 jobs, 100 of them Code 1, pending. Of the nine people who lost their lives in the epidemic, it is believed that at least two died while waiting for an ambulance, including 20-year-old Hope Carnevali, who died on the front lawn of her home in Hoppers Crossing, about 30 kilometres south-west of Melbourne's CBD.

Experts believe that, until November 21, 2016, the world's only known thunderstorm-associated asthma death was in the UK in 2002. Several Australian thunderstorm asthma events have been recorded over the years, always in spring when the pollen load is at its greatest, but newspaper archive searches reveal only a few small reports: 154 cases of asthma presenting at Melbourne hospitals in 1987, the first time the term "thunderstorm asthma" seems to have been used; two people requiring intubation and artificial ventilation in Wagga Wagga in 1997; more than 300 respiratory cases requiring ambulances after a thunderstorm in Melbourne in November, 2010.

Ahead of spring 2011, three Melbourne respiratory specialists co-signed a letter to the Medical Journal of Australia warning of the thunderstorm asthma season's approach, but it passed without incident and the letter into archives. In the aftermath of last November's event, some health professionals confessed they'd never even heard of the phenomenon, an almost supernatural conflation of sciences: meteorology, physics, botany, medicine and demography. Thunderstorm asthma remains an interdisciplinary detective story. First, though, it's a health emergency.

Through winter and spring, the rain fell. In Victoria, September 2016 was the second wettest September on record. November started with rain on Melbourne Cup Day. Meanwhile, the grass was growing. As it did, so, too, did the source of hayfever sufferers' torment: pollen drifting in the air.

On Monday, November 21, summer arrived early. At 8.39am, it was 27°C in the city and commuters took to Twitter to complain about stinking-hot train carriages. The Bureau of Meteorology (BOM) predicted the temperature would hit 38°C later in the day. Warnings were issued about extreme levels of pollen. By 4pm, it was 34.4°C and a strong north-north-westerly wind was blowing.

Through the afternoon in Sunshine West, Jackie Falzon, a livewire brunette, her fiancé, Matthew Sposato, and their son, Frankie, were sheltering from the heat and watching the animated children's show Paw Patrol. "I made sure I stayed in so that my son wouldn't get burnt," she recalls. Around 4pm, she took him into her bedroom in the house she shares with Sposato and his parents and they both fell asleep. She'd heard a storm was forecast but yeah, she thought, a storm, whatever.

Meteorologists can see days ahead that the conditions required for the formation of storm cells will be present, but it's not until a storm starts to build and is seen on a radar that it can be studied and warnings can be issued if it has the potential to do damage or cause injury. At 5.13pm on November 21, the BOM issued a severe storm warning for damaging winds, heavy rainfall and large hail.

At Footscray Hospital, senior nurse Chantelle D'Souza was in a staffroom on her tea break and noticed the ominous clouds through the window. Dr John Loy, acting director of the hospital's ED, who was at home in Melbourne's east, heard a news update about the storm, felt the wind pick up and told his two young children playing on the deck to come inside for dinner and close the door. In Keilor East, about 17 kilometres north-west of Melbourne's CBD, Elisabeth Paterson's 24-year-old son, Dale, was in their backyard firing up the barbecue.  

He hadn't told his mother but he was having trouble breathing. The sky was grey and, at one point, tree branches thrashed in a whirling dervish of a wind. But the family is Scottish. "We would call that 'barbecue weather'," says Paterson, a psychiatric nurse who works on the Footscray Hospital campus.Around 5.30pm, Jackie Falzon was woken from her nap by her crying baby. Quickly she realised she had asthma. She got up and used her Ventolin puffer. It didn't help. She used it two more times. As Falzon held onto the kitchen bench and hunched her shoulders over in what doctors call the "tripod position" and which asthmatics adopt to try to get in more air, she heard the rain. "It pelted down like for five seconds. It came and went."

Still, she couldn't breathe. She returned to her bedroom to try her nebuliser, a machine that turns medication into a vapour that can be inhaled. "Our bedroom's like a hot box; I think it sort of made it worse." By 6pm, she was panicking. Sposato dialled 000. Falzon remembers paramedics Scott Drysdale and Sebastian Smialy coming into her room. She recalls gasping for breath and sobbing in terror and Drysdale looking into her eyes and telling her to breathe.

A few days later, a senior paramedic would tell Drysdale that it was unlikely he would ever again in his career manage a sicker patient without back-up from at least one MICA paramedic. Normally, a patient would be stabilised before the ambulance started to move – with more than one paramedic in the back.

And normally, the driver would drive steadily to minimise movement. Drysdale and Smialy knew that, in Falzon's case, there was no time for normal procedures. At 6.22pm, about 10 minutes after arriving at the house, Drysdale told his partner: "I just want you to drive, and drive quick."

He also wanted Smialy to keep talking: it's procedure for paramedics to talk through their guidelines, to verbalise what they're doing and what must be done next. Smialy could hear in his partner's voice that he was anxious. Drysdale had put defibrillation pads on the unconscious Falzon's chest – just to be prepared. He'd given her a second, then a third shot of adrenaline, but her oxygen saturation levels were now precipitously low at 85 per cent.

Soon after pulling away from the kerb, Falzon stopped breathing. Using a "bag valve mask" – a manual resuscitator, Drysdale took over her breathing, squeezing a balloon-like bag, attached to a mask on her face and an oxygen-delivery device, to force air into her lungs.

"You're doing well," Smialy told him from the driver's seat. "You're doing well." At 6.31pm, in the back of an ambulance on the Western Ring Road, Jackie Falzon's pulse dropped out.

Just after 6pm, in his backyard in the inner-northern suburb of Brunswick, Dr Philip Taylor stood beneath the thunderstorm's outflow. There was something of the mad scientist in his demeanour; moments before at his computer, he had watched a red bar move across the BOM's Doppler radar loop – "a stunning movie" of the storm's relative wind speed, humidity and temperature.

Now, intoxicated with his science, he wanted to feel the numbers he'd seen on his screen, feel the physics of the storm. "The wind was going in every possible direction, it was totally unstable around me," says Taylor, an environmental allergist and research fellow at Deakin University's Centre for Cellular and Molecular Biology who, in 2012, helped to establish the world's only thunderstorm-associated asthma warning system, the volunteer-run Deakin AIRwatch.

The day before, after pollen samples were taken at stations in Geelong and at the university's Burwood campus in Melbourne's east, AIRwatch issued a thunderstorm asthma risk forecast of "extreme" for the Monday. The spring rain had guaranteed that the conditions needed for an incident were all there. But like the phenomenon itself, the AIRwatch website is little-known; only 19 people visited it on the Sunday and Monday.

All evidence suggests that thunderstorm asthma starts with perennial ryegrass, Lolium perenne, an introduced species that supplanted indigenous grasses in the earliest days of the colonies. (It is a different species from that which produces the rye grain for rye flour.) Between October and December, it is the dominant flowering grass through Melbourne's suburbs – on nature strips, sports fields and in backyards – and in farmland from the city's outskirts to the Western Districts. Now the ryegrass was lusher than it had been in years.

The characteristic that makes Lolium perenne such a fine pasture grass and hay – it is naturally vigorous – is perhaps why it is the very devil for hayfever sufferers. Compared to other grasses, ryegrass produces huge volumes of pollen and, within each pollen grain, there is a massive loading of allergenic proteins. (Research conducted by Taylor and his Deakin colleague, associate professor Cenk Suphioglu, found that 95 per cent of people who suffered respiratory distress in the 1987 thunderstorm asthma incident were allergic to ryegrass pollen.)

On Monday, November 21, the ryegrass pollen load was extreme – in excess of 100 pollen grains per cubic metre of air. At about 30 micrometres in diameter (30 times smaller than a millimetre), ryegrass pollen grains can embed themselves in an eye or a nostril and wreck a hayfever sufferer's day. But they are too large to get into a person's lower airways, the bronchi and bronchioles. Given certain conditions though, they can shatter into particles small enough to be inhaled deeply.

In meteorological terms, the north-south band of towering cumulonimbus clouds that swept in from the west across Geelong and the city formed a garden-variety spring thunderstorm, albeit a severe one. "All absolutely normal for the Melbourne climate," says Tarini Casinader, the BOM's Victorian regional director. It was what happened inside the clouds that was exceptional and which largely remains a scientific mystery.

Experts hypothesise that masses of intact pollen grains from western pastures were sucked up into the warm updraft of air forming the storm cells. In the humid base of the swirling clouds, the pollen grains exploded. The ruptured pollen returned to earth in the storm's cool downdraft, then was spat out across the ground in the storm's outflow area, or gust front, which was moving just ahead of the storm at 60 kilometres an hour.

Philip Taylor's research has led him to think that there might be singularities within a storm cell that can intensify a pollen explosion, including humidity levels and the nature of the electric field, and which may have been responsible for the unprecedented mass nature of the event. Casinader adds another thought: "The most important thing may be timing; if the thunderstorm outflow is at its strongest exactly when it's passing over a population centre."

What seems to be likely is that the outflow, the crazy wind that was the storm's grim herald, carried a fine, invisible and lethal mist. When Jackie Falzon leant on the kitchen bench at her Sunshine West home and heard the rain come down, the ryegrass pollen particles had already swept through the suburb and settled into her airways.

At 6.38pm, half an hour after Taylor exalted in a spring storm, Sebastian Smialy swung his ambulance, lights flashing, sirens screaming, into the ED driveway at Sunshine Hospital. In the back, Scott Drysdale, sweat-drenched, was still "bagging" the unconscious Falzon. Within minutes, she had been raced on a stretcher into an ED resuscitation bay, its curtains yanked to a close, and a team of six doctors and nurses surrounded her.

About the same time, Ambulance Victoria staff in ESTA's Burwood East communications centre were looking at the rapidly spreading number of green dots on their screens indicating cases requiring attention and wondering whether their equipment was malfunctioning.

"it's okay, you're here now." A nurse in the Sunshine Hospital ED clearly read something in Drysdale's face. He and his partner, Sebastian Smialy, had just handed Jackie Falzon into the care of doctors. Drysdale remembers the nurse reassuring him and the feeling of his heart beating.

When Falzon's pulse had stopped in the ambulance, Drysdale had cursed, then followed paramedic protocols: he removed the mask and allowed for a minute of apnoea – the cessation of breathing – which can get the blood pumping around the heart again. The hospital was still seven minutes away, a lifetime in a case such as this. If Falzon needed CPR, Smialy would have to pull over to the side of the road so one of the paramedics could work on her heart while the other continued ventilating her. In that minute of apnoea, Falzon's pulse returned, although for the remainder of the drive, Drysdale would keep hand-ventilating her.

In the resuscitation bay now, Falzon was in the hands of Dr Barry Gunn, the emergency physician at Sunshine ED that night. It was clear she needed to be immediately intubated – a procedure in which a tube is inserted into a patient's trachea to open the airways and allow for controlled artificial ventilation, optimising oxygen concentration and the flow of air in and out of the lungs. 

"She was extremely, dangerously ill," says Gunn.

All asthma is thought to have an allergic basis, with different sufferers responding to different triggers, including pollen, dust mites, mould spores and pet dander. But doctors believe that thunderstorm-induced asthma resembles anaphylaxis, the most severe form of allergic reaction, particularly in the way it strikes so suddenly and affects people who previously might only have suffered hayfever. "Some people get sick so quickly that even if they had asthma medication to hand, it might not matter," says associate professor Craig French, the director of Intensive Care across Western Health.

For someone in the throes of an asthma attack, breathing out, not in, is the biggest challenge. The swollen airways are unable to empty of gas and the bloodstream is flooded with poisonous carbon dioxide, which causes unconsciousness. Intubating any unstable patient in an emergency situation is fraught with risk; in the case of an asthma patient who might have stopped breathing, the tube might slide down their throat but there is always the possibility that the lower airways will be too tight for the procedure to work and, as time rushes on, the risk of cardiac arrest increases.

As Gunn's team rushed to insert an IV cannula into Falzon's arm through which she would receive drugs including an anaesthetic-type sedative, adrenaline and other muscle relaxants, and to attach her to an array of equipment to monitor her blood pressure, oxygen saturation, breathing and heart rate, there was something else on his mind. Even if they could successfully ventilate her, it might turn out that she had already suffered a brain injury from lack of oxygen.

In an ED corridor, Drysdale bumped into Falzon's fiancé, Matthew Sposato, who had driven separately to the hospital. "Is she going to live?" Sposato asked. The paramedic told the emotional young man that the situation was extremely serious. All around them, doctors and nurses were scrambling to manage the influx of people in respiratory distress.

In a "resus" bay just near where Gunn was intubating Falzon, another team's focus was on a critically ill 12-year-old girl who was quickly transferred to the Royal Children's Hospital. In the waiting room, which was filling with people, a woman collapsed. A nurse whom Drysdale knew was battling to triage an increasing line of patients and was close to tears. "I don't know what's happening; I've called, but no one's come," she told him.

Around the same time at Footscray Hospital, doctors were attempting to intubate two dangerously ill patients. One was a "walk-in", a taxi driver in his 60s who had driven to the hospital and got himself into the ED waiting room, before quickly deteriorating. Dr Karen Winter, Footscray's emergency specialist in charge for the night, remembers his face. "He was obviously very scared and distressed."

Associate nurse unit manager Chantelle D'Souza was in the "fishbowl" – the ED's open office area opposite the department's three resuscitation bays – as Winter started to intubate the driver. Normally, Winter would have had a team of up to six clinicians assisting with the process, but the department was so stretched that only one nurse was with her. "Suddenly he was just profusely sweaty, really combative, probably [from] anxiety and probably lack of oxygen. He was fighting; he was quite a solid man," D'Souza recalls. "I managed to get security to just help and hold him down." But Winter was still up against it: medication to settle the spasms in the man's airways hadn't yet kicked in and intubating him in the ED proved to be impossible. "We had to hand-ventilate him until we got him up to intensive care, where we could use their ventilators."

D'Souza, a longtime asthmatic herself, was gasping for breath and had been using her Ventolin puffer: "I just didn't want to let it get the better of me because I had a job to do." In the fishbowl, she leaned against a high desk, hunched in the tripod position, and worked the phone. She needed night staff who were due in at 11pm to come in as soon as they could.

"Get yourself treated," a senior colleague told her. At about the same time that D'Souza was setting herself up in a back room with a portable oxygen cylinder, mask and Ventolin nebuliser, call-takers at ESTA in Burwood East were repeating themselves: "Go ahead caller, where do you need the ambulance?" Between 7 and 7.15pm, as the crisis escalated, emergency calls were landing at a rate of one every 4.5 seconds.

About 8pm at their home in Keilor East, Elisabeth Paterson's son, Dale, put his face into the freezer. It was something the asthmatic had done for years: the cold air seemed to help clear his airways. After the storm had passed and the family had finished their barbecue, the soccer-loving student's chest had grown even tighter. "I think he was using the Ventolin a wee bit more excessively than normal," recalls Paterson. But she didn't take much notice: he was 24 and managed his asthma himself.

As Dale was working to slow his breathing, 10 kilometres away the Footscray ED was in a frenzy. Between 8 and 9pm, 37 ambulances pulled into a facility with designated bays for only three vehicles. Paramedics wheeled critically ill patients on stretchers through the carpark and past queues waiting outside the door to the ED waiting room, while gawkers took photographs.

Associate nurse unit manager Nerina Fiamengo was one of the off-duty nurses called in to help. She arrived at Footscray at 8pm and headed into the waiting room, which was full of people in the tripod position and anxious, hovering family members. With training in disaster management, Fiamengo worked to implement a triage production line to take patient details and determine how urgent their case was. "It was just chaos, there were people everywhere."

At one point, a shirtless and evidently drug-affected young man wandered into the waiting room. "Hey guys, youse are doing an amazing job, I love your work," he said. Fiamengo recalls him leaving, then returning with another positive message. "It made everyone giggle for a time." She told him she was grateful for his words but it probably wasn't the best time to keep coming in.

Emergency specialist Karen Winter had called her boss, acting ED director John Loy, and, at 9pm, he returned to find the department steamy, shrouded with the mist of nebulisers and noisy with beeping ventilators. He took stock: across the department, patients were receiving the three-pronged treatment approach to serious asthma: oxygen, plus steroids to dampen the immune system and reduce inflammation, and Ventolin to relax airways. In the blue, sub-acute area in cubicles designed for one, half a dozen masked patients sat sharing a wan and wheezy camaraderie. In the red, acute area, each cubicle was full and three patients were on non-invasive ventilation machines, receiving oxygen and medication behind tight-fitting face masks. In each of the three resuscitation bays, there was a dangerously ill asthma victim.

"There were 12 critical, touch-and-go asthmas that needed a lot of senior review," says Loy. "You're on the phone all the time – 'What's happening? Has that person gone to intensive care yet? Is that bed available? How's number 9? They're trending okay. How's number 7? Do you want to come look at 6? I've got another three ambulances waiting to come in, where are we going to put them?' " And amid it all, others needing assistance: a man who'd fallen off a ladder, another with a broken leg, an elderly woman who'd had a stroke.

At midnight, there were still 100 patients at Footscray ED. Elisabeth Paterson's son was soon to become another one. Just before 10pm, Paterson had driven to a nearby pharmacy to see what she could buy to assist Dale's breathing. She returned home with a spacer, a device used with a puffer to improve its efficacy. A little while later, she checked in on him. He told her he didn't feel worse. "He was still able to converse with me," she says. "I thought, 'Well, let's see how this works.' "

For Paterson, it had been a stressful week and she was exhausted: her husband had just come out of hospital after an operation and was still immobile. She went into her bedroom and quickly fell asleep on top of the bed. Some time after 1am, her husband called out to her from the lounge room where he was sitting up. Their son was in trouble. Paterson rushed into his room. "He said, 'I feel as though I'm going to die, the pain in my back … I've never felt anything like this in my life before.' "

Now, Paterson puzzles over her thinking. "I never even thought to phone an ambulance." She remembers a quick discussion with her husband about which hospital to go to and deciding on Footscray, because it was where she worked. She remembers empty roads, bar one car that seemed barely to be moving, and glancing at her son and realising he was turning blue. He spluttered out that he was going to throw up. She knew she had to keep driving no matter what. At 2.32am, mother and son stumbled into the still-crowded waiting room of Footscray ED. Nurse Nerina Fiamengo took one look at Dale and rushed him in for treatment.

Paterson had imagined that, after a bit of medication, her son would be right to go home with her. By 11am the following morning, he had been admitted to the hospital's intensive care unit (ICU). ED treatment, including non-invasive ventilation, had brought down his respiratory and heart rates and his oxygenation had improved, but he needed the attention a normal ward could not provide.

"I was a wreck; I was so upset," says Paterson. "I felt really guilty that I hadn't been aware of the extent of what was happening. I was really worried that they wouldn't be able to stabilise him." She sat at her son's ICU bedside. "I just held his hand and said, 'Look, I'm really, really sorry.' " He said, 'That's okay, that's okay.' " Dale would spend several more subdued days in hospital; his mother sensed that he was ruminating on his encounter with mortality. She thinks back to the night of the storm: "I think he was very scared."

In the months ahead, through coronial investigations and inquiry findings, there will be conclusions drawn about failures in resourcing and weaknesses in systems and science that likely contributed to the tragic deaths of nine Melburnians and left countless others fighting for that most elemental thing – breath.

As environmental allergist Philip Taylor puts it: "A storm that went through the sky has gone through science and through the government and the health department." His own life's work has gained attention like never before. "This is such a rare and esoteric event in science because you need medicine, botany, atmospheric physics, atmospheric chemistry ... so many different fields; that's what makes me really excited about working on it."

As for Jackie Falzon: she knows now what happened after she lost consciousness. She knows how perilously close she came to full cardio-respiratory arrest in the back of an ambulance. She has heard how, around 7pm in the ED of Sunshine Hospital, Dr Barry Gunn smoothly intubated her and how her breathing and heart rate stabilised and her carbon dioxide levels started to decrease. She can picture herself being wheeled through the hospital corridors, unconscious and attached to a breathing machine, on the way to the hospital's ICU. 

Late Tuesday afternoon, November 22, about 24 hours after paramedics Smialy and Drysdale arrived in her bedroom, Falzon started to recover consciousness and ICU director Craig French removed the tube from her throat that had kept her alive.

"Hey, baby," her partner Matthew Sposato said as she woke. She thought she'd been asleep maybe an hour. She asked him whether he'd been to football training. Her mother arrived at her bedside and they both started crying. "We almost lost you," her mother said. Falzon tried to explain what had happened while she slept: she had heard her Maltese grandmother's voice. "She was saying to me in Maltese, 'Come on, wake up, it's time now. Ejja qum.' " 

The Age