Sometimes, the world gets thrown off its axis, and such disorders defy description. Unlike déjà vu, these situations leave us with no familiar feelings, only foreign frustrations. Scholar Karl Weick labelled such strange moments “cosmology episodes.”

Brian Collins’s personal cosmology episode began in April 2010, with tea, toast, and BBC breaking news. “The bloody thing just exploded, and I couldn’t pronounce it,” Collins recalled. “You have to speak from somewhere down there below your larynx.” He referred to the volcano Eyjafjallajökull (AY-yah-fyah-lah-YOH-kuul), a glacier atop the mountain overlooking the Icelandic islands. Collins’s pronunciation had a bass-baritone tremor, rhyming like “I forgot the yoghurt.” Time magazine later declared Eyjafjallajökull one of the top 10 buzzwords of 2010, in the company of “austerity,” “anchor babies,” “bedbugs,” and “Bunga Bunga.”

When Eyjafjallajökull exploded, Brian Collins was the chief scientific adviser to the UK Department for Transport, responsible for coordinating an emergency response. “It was a bugger because it came down, went round a low, and then came back again,” Collins recalled about the ash plume. “It wasn’t a density issue; it was an accumulation issue.” Despite warnings, the UK government didn’t anticipate the consequences. After all, the pilots in the UK were used to cloudy takeoffs and landings.

Public emotions erupted over the subsequent week – a stoppage that lasted twice the duration of the shutdown of American airspace after the 9/11 attacks. Airline executives called the shutdown “scandalous.” Among those desperate to travel, a group of corporate lawyers was willing to pay six-figure sums for a private aircraft and crew but found no takers. The Monty Python legend John Cleese took a taxi from Oslo to Brussels and recalled an old joke to a reporter: “How do you get God to laugh? Tell him your plans.” The Royal Navy and private luxury liners came to the rescue, repatriating civilians stranded in different parts of the world and evoking comparisons to the Miracle of Dunkirk.

In early 2009, the year before its eruption, Eyjafjallajökull moaned with multitudes of mild earthquakes. The ice-topped stratovolcano, about 75 miles east of Reykjavík and 1,000 miles from London, is part of southern Iceland’s east-west range of faults and fissures. After the slow start, the summit boomed on March 20, 2010. Eyjafjallajökull blazed against the emerald northern lights with a mixture of strombolian lava bombs and Vulcanian cannon fires. The result was a “tourist eruption” or, as one scientist put it, a “volcano Disneyland.” Ignoring safety warnings, hundreds of sightseers took to super Jeeps, snowmobiles, and quads. Others witnessed the wheezing warmth of the fire fountains from helicopters. Two visitors died.

The volcano rekindled on April 14 and began expelling magma from beneath the glacier. Meltwater flooded the region, forcing evacuations. Heat-cold reaction roared out plumes of fine ash reaching 32,000 feet, ultimately dispersing over 250 million tons. About 60 per cent of the ash was silica; over a quarter of the particulate matter was under 10 microns in diameter, posing significant cardiovascular and respiratory risks. One official impulsively equated the event to the 1986 Chernobyl nuclear disaster, likening its ash to radiation. In his 1922 poem “The Waste Land,” TS Eliot wasn’t predicting Eyjafjallajökull when he wrote, “I will show you fear in a handful of dust.” But fear and dust did spread as the 2010 “ashpocalypse” travelled furiously across European airspace. Although its impacts felt surprising, like all volcanoes, Eyjafjallajökull was predictable.

In 1822, when human flight was still a futuristic fancy, Eyjafjallajökull spewed a sporadic smokestack of clouds. Since this last eruption, with increased transcontinental air traffic beginning in the 1970s, volcanic dust has become a more serious threat to aviation. A local disturbance can now bring the global economy to a standstill. In this case, it did. The London Volcanic Ash Advisory Centre, run by the UK’s National Weather Service, put out an advisory. The International Civil Aviation Organization guidance instructed pilots to avoid volcanic ash. The “zero tolerance” for ash inherently buckled the busy hubs of Heathrow, Frankfurt, and 300 more airports, creating the continent’s “worst peacetime aviation crisis.” In a week, cancelling over 100,000 flights stranded 10 million passengers during the Easter holidays, slamming the airline industry with over $1.7 billion in losses. The shutdown also damaged some African economies. For instance, Kenya exports about 500 tons of fresh flowers to Europe daily. With grounded cargo, growers furloughed thousands of workers.

Of course, the idea that volcanic ash can be problematic isn’t novel. Between 50 and 70 volcanoes erupt yearly. Scholars Amy Donovan and Clive Oppenheimer point out that there are currently over 700 volcanoes located within 60 miles and over 1,300 volcanoes within 150 miles of international borders, each with effects that can cross borders. On June 8, 1783, 28 years after an eruption of “Angry Sister” Katla that Iceland was still recovering from, hell broke loose again. The Laki craters belched a fire fountain, spewing poisonous ash into the pastoral landscape. Within minutes, everything turned dark; a blizzard of powder-like coal ash fell out of the clouds. For the next 12 days, Laki spilled two Olympic swimming pools of lava each second. Over the next eight months, sulfur-rich effluvium rose into the heavens, creating a haze that Benjamin Franklin feared “was of a permanent nature.” The volcanic veil cooled the world and collapsed communities; the death of livestock and crops fueled famines, perhaps even contributing to the French Revolution. The Nile and the Niger shrank; tens of thousands succumbed to breathing problems in Europe, and far more perished over the years from the ensuing drought and hunger stretching from Iceland to India.

But ash’s specific threat to aircraft became obvious on a summer night in 1982 over Indonesia. A British Airways 747 to New Zealand flew into ash from the growling Galunggung volcano. Passengers first assumed that the smoke inside the cabin was from cigarettes. Then the first engine flamed out, and the remaining three failed within minutes. The pilot made a heroic announcement: “We are doing our damnedest to get them going again. I trust you are not in too much distress.” It became a “masterpiece of understatement.” The pilot glided the aircraft from 37,000 feet over a dramatic 23 minutes, managing to restart three engines during the descent. The plane made an emergency landing in Jakarta using a two-inch view on the side window clear of ash. All the 263 passengers and crew landed unhurt.

Within days of this extraordinary event, a Singapore Airlines jumbo to Australia experienced something similar, as did a KLM 747 a year later over Alaska. The Redoubt volcano burped vaporous ash, blanketing nearly 8,000 square miles. The mechanical damage to the aircraft cost over $80 million. And in 1991, the hot and hostile awakening of Mount Pinatubo in the Philippines destroyed a $100 million aircraft. Despite these experiences, the aviation industry had not proactively conducted tests to determine how much ash the turbines could handle before they failed.

For an aircraft operating at 600 miles per hour, volcanic ash is mechanically, electrically, and chemically asphyxiating. The melting temperature of the ash is close to the operating temperatures of large engines, which puts aeroplanes at risk of an immediate shutdown if they fly through volcanic plumes. The “zero tolerance” policy in 2010 was controversial because the Eyjafjallajökull ash could be sensed only by radar, LIDAR, and infrared satellites. It was invisible to the naked eye. The CAA, the UK’s Civil Aviation Authority, wouldn’t take the risk of prematurely reopening the airspace, even partially. It now needed to confirm the “safe” ash levels for flight, which required real-time tracking of ash clouds.

The CAA asked the Met Office to run its Numerical Atmospheric-dispersion Modelling Environment code to produce ash-concentration charts. The CAA also tasked airframe and engine manufacturers to determine safe thresholds for flight. Lacking time, data, and insights into the damage patterns, the modellers confronted unavoidable uncertainties. Their vagueness stemmed from inexact knowledge; some had to extrapolate from previous ash encounters of Redoubt and the Galunggung. The industry developed a “Safe-to-Fly” chart with multiple levels of probability modelling.

Back in Westminster, “messy vagueness” was brewing. Brian Collins and the interagency team were vexed with a situation out of solutions and out of control. There were many stakeholders, some already very upset at the financial and social impacts. Getting community members to understand and respond to an invisible threat can mean disagreements. Still, Collins trusted the process of convening and coordination. Starting April 16, 2010, the CAA brought over 100 organizations worldwide into discussion. “We met seven or eight times a day with hundreds of participants to make various bits of this jigsaw come together,” Collins said. From jet engine manufacturers to regulators, insurers, and public officials, the participants had different views, and reconciling them wasn’t always easy. But their common goal was to reopen the airspace safely. If dialogues can cause messy vagueness, they can also help dissolve it. Sometimes it’s about simply waiting out a temporary crisis; sometimes, it’s about using the winds of an emergency to unite people who need to work together for mutual safety; sometimes, it’s both, and sometimes, it’s neither. “No one talks or writes about the importance of these discussions,” Collins said, “because they are not newsworthy.”

On April 20, 2010, the industry reported two milligrams per cubic meter of air as an acceptable safety limit for flight operations, and the CAA agreed to that requirement. Later that day, European airspace lifted the travel ban. At the same time, test aircraft monitored Eyjafjallajökull’s ash until the ejection rates subsided 10 days later. Passengers arriving at the UK airports were jubilant. One passenger compared the feeling of getting the boarding pass to “winning a golden ticket to Willy Wonka’s chocolate factory.” The Guardian pondered “how liberating it is sometimes to be powerless before nature.”

That evening, Collins returned home exhausted and sleep-deprived. He sat on his couch with a beverage and flicked on the BBC. Slowly his eyes widened to the channel’s jarring split screen. One half showed the continued earthy effervescence of Iceland. The other broke the news of a human-made eruption. The Deepwater Horizon marine rig was aflame across the Atlantic. Over the next three months, tireless torrents of toxic crude gushed four million barrels into the Gulf of Mexico.

Excerpted with permission from Wicked Problems: How to Engineer a Better World, Guru Madhavan, HarperCollins India.