Though it might not sound like it, a “bomb cyclone” is a legitimate scientific term, so named because the rapid formation of the storm is like a bomb going off.
Millions of Americans have been warned to brace for a bomb cyclonewith blizzard conditions, wind chills and temperatures plunging as low as -45.6C (-50.1F) – cold enough to get frostbite in less than five minutes.
A bomb cycloneor “weather bomb” is a term used to describe a rapidly deepening area of low pressure.
“More correctly, it should be called explosive cyclogenesis, which is when the central pressure of a low pressure system falls dramatically – by 24 millibars in 24 hours,” Sky News weather presenter Kirsty McCabe said.
“These intense storms bring heavy precipitation and very strong winds. In the US right now, very cold Arctic air is being pulled in, with the freezing weather causing further complications.”
How does a bomb cyclone form?
The sudden change in pressure is due to interactions with a powerful jet stream, McCabe said.
“This is the fast-moving ribbon of air high in the atmosphere that steers our surface low pressure systems around.
“The contrast between cold, Arctic air in the north and warm, tropical air in the south has strengthened the jet stream, which in turn deepened the area of low pressure.”
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Image: Overnight lows from Friday night into Saturday morning (temperatures in Celsius)
Why is it called a bomb cyclone?
Meteorologists have likened the sudden drop in pressure to a bomb going off, using words such as “explosive cyclogenesis” and “bombogenesis” to describe the storm’s formation process.
The term specifically refers to the speed at which a storm forms, Daniel Swain, a climate scientist at the University of California, said.
“It doesn’t necessarily refer to the absolute strength of the storm system,” he said.
Does the UK get bomb cyclones?
The UK has experienced weather bombs, most famously the Great Storm of 1987.
Image: Wrapping up as snow begins to fall in St Louis, Missouri. Pic: AP
How does a bomb cyclone differ from a hurricane?
“All bomb cyclones are not hurricanes,” Mr Swain said. “But sometimes, they can take on characteristics that make them look an awful lot like hurricanes, with very strong winds, heavy precipitation and well-defined eye-like features in the middle.”
Hurricanes tend to form in tropical areas and are powered by warm seas. For this reason, they’re most common in the US in summer or early autumn, when seawater is warmest.
In contrast, bomb cyclones don’t need balmy ocean waters to form.
They can appear over land as well as the sea and are most common between late autumn and early spring, when warm tropical air bumps up against frigid Arctic air.
“They have to occur at a time of year when there is some possibility of both warm and cool air at the same time,” Mr Swain said. It’s the difference in temperature that fuels the drop in pressure.
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US set to suffer its coldest Christmas in more than 40 years
Are bomb cyclones dangerous?
It depends. Sometimes, bomb cyclones behave like conventional winter storms.
But sometimes they produce heavy flooding, blizzard conditions and wind speeds comparable to a Category 1 hurricane.
“Fundamentally, the impacts of a bomb cyclone are not necessarily different from other strong storm systems, except that the fast strengthening is usually a signature of a very powerful storm system,” Mr Swain said.
Much of the danger lies in the fact that bomb cyclones can take people by surprise, he added.
Global financial markets gave a clear vote of no-confidence in President Trump’s economic policy.
The damage it will do is obvious: costs for companies will rise, hitting their earnings.
The consequences will ripple throughout the global economy, with economists now raising their expectations for a recession, not only in the US, but across the world.
While the UK’s FTSE 100 closed down 1.55% and the continent’s STOXX Europe 600 index was down 2.67% as of 5.30pm, it was American traders who were hit the most.
All three of the US’s major markets opened to sharp losses on Thursday morning.
Image: The S&P 500 is set for its worst day of trading since the COVID-19 pandemic. File pic: AP
By 8.30pm UK time (3.30pm EST), The Dow Jones Industrial Average was down 3.7%, the S&P 500 opened with a drop of 4.4%, and the Nasdaq composite was down 5.6%.
Compared to their values when Donald Trump was inaugurated, the three markets were down around 5.6%, 8.7% and 14.4%, respectively, according to LSEG.
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Worst one-day losses since COVID
As Wall Street trading ended at 9pm in the UK, two indexes had suffered their worst one-day losses since the COVID-19 pandemic.
The S&P 500 fell 4.85%, the Nasdaq dropped 6%, and the Dow Jones fell 4%.
It marks Nasdaq’s biggest daily percentage drop since March 2020 at the start of COVID, and the largest drop for the Dow Jones since June 2020.
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5:07
The latest numbers on tariffs
‘Trust in President Trump’
White House press secretary Karoline Leavitt told CNN earlier in the day that Mr Trump was “doubling down on his proven economic formula from his first term”.
“To anyone on Wall Street this morning, I would say trust in President Trump,” she told the broadcaster, adding: “This is indeed a national emergency… and it’s about time we have a president who actually does something about it.”
Later, the US president told reporters as he left the White House that “I think it’s going very well,” adding: “The markets are going to boom, the stock is going to boom, the country is going to boom.”
He later said on Air Force One that the UK is “happy” with its tariff – the lowest possible levy of 10% – and added he would be open to negotiations if other countries “offer something phenomenal”.
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3:27
How is the world reacting to Trump’s tariffs?
Economist warns of ‘spiral of doom’
The turbulence in the markets from Mr Trump’s tariffs “just left everybody in shock”, Garrett Melson, portfolio strategist at Natixis Investment Managers Solutions in Boston, told Reuters.
He added that the economy could go into recession as a result, saying that “a lot of the pain, will probably most acutely be felt in the US and that certainly would weigh on broader global growth as well”.
Meanwhile, chief investment officer at St James’s Place Justin Onuekwusi said that international retaliation is likely, even as “it’s clear countries will think about how to retaliate in a politically astute way”.
He warned: “Significant retaliation could lead to a tariff ‘spiral of doom’ that could be the growth shock that drags us into recession.”
It comes as the UK government published a long list of US products that could be subject to reciprocal tariffs – including golf clubs and golf balls.
Running to more than 400 pages, the list is part of a four-week-long consultation with British businesses and suggests whiskey, jeans, livestock, and chemical components.
Meanwhile, Prime Minister Sir Keir Starmer said on Thursday that the US president had launched a “new era” for global trade and that the UK will respond with “cool and calm heads”.
It also comes as Canadian Prime Minister Mark Carney announced a 25% tariff on all American-imported vehicles that are not compliant with the US-Mexico-Canada trade deal.
He added: “The 80-year period when the United States embraced the mantle of global economic leadership, when it forged alliances rooted in trust and mutual respect and championed the free and open exchange of goods and services, is over. This is a tragedy.”
Tanking stock markets, collapsing world orders, devastating trade wars; economists with their hair ablaze are scrambling to keep up.
But as we try to make sense of Donald Trumps’s tariff tsunami, economic theory only goes so far. In the end this surely is about something more primal.
Power.
Understanding that may be crucial to how the world responds.
Yes, economics helps explain the impact. The world’s economy has after all shifted on its axis, the way it’s been run for decades turned on its head.
Instead of driving world trade, America is creating a trade war. We will all feel the impact.
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PM will ‘fight’ for deal with US
Donald Trump says he is settling scores, righting wrongs. America has been raped, looted and pillaged by the world trading system.
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But don’t be distracted by the hyperbole – and if you think this is about economics alone, you may be missing the point.
Above all, tariffs give Donald Trump power. They strike fear into allies and enemies, from governments to corporations.
This is a president who runs his presidency like a medieval emperor or mafia don.
It is one reason why since his election we have seen what one statesman called a conga line of sycophants make their way to the White House, from world leaders to titans of industry.
The conga line will grow longer as they now redouble their efforts hoping to special treatment from Trump’s tariffs. Sir Keir Starmer among them.
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President Trump’s using similar tactics at home, deploying presidential power to extract concessions and deter dissent in corporate America, academia and the US media. Those who offer favours are spared punishment.
His critics say he seeks a form power for the executive or presidential branch of government that the founding fathers deliberately sought to prevent.
Whether or not that is true, the same playbook of divide and rule through intimidation can now be applied internationally. Thanks to tariffs
Each country will seek exceptions but on Trump’s terms. Those who retaliate may meet escalation.
This is the unforgiving calculus for governments including our own plotting their next moves.
The temptation will be to give Trump whatever he wants to spare their economies, but there is a jeopardy that compounds the longer this goes on.
Image: Could America’s traditional allies turn to China? Pic: AP
Malcolm Turnbull, the former Australian prime minister who coined the conga line comparison, put it this way: “Pretty much all the international leaders I have seen that have sucked up to Trump have been run over. The reality is if you suck up to bullies, whether it’s global affairs or in the playground, you just get more bullying.”
Trading partners may be able to mitigate the impact of these tariffs through negotiation, but that may only encourage this unorthodox president to demand ever more?
Ultimately the world will need a more reliable superpower than that.
In the hands of such a president, America cannot be counted on.
When it comes to security, stability and prosperity, allies will need to fend for themselves.
And they will need new friends. If Washington can’t be relied on, Beijing beckons.
America First will, more and more, mean America on its own.