There was the legendary "Carrington Event," a series of magnetic storms from the sun that hit the Earth in August and September of 1859, disrupting telegraph lines across the U.S.
and triggering auroras so bright they turned the night skies into day as far south as the Caribbean. The storm went on for days.
They spoke of a solar storm in May of 1921 that stunned scientists with its power, and one in March of 1989 that blacked out the entire power grid in Quebec in just 92 seconds.
In 2003, the "Halloween storm" caused a massive blackout in the Northeast U.S. and $10 billion worth of damage to electrical systems.
There are lessons to be learned from these past events, the researchers emphasized, and the danger posed by solar storms is increasing.
This growing threat comes not from changes in the Sun, but from the increasing dependence of human societies on technology and electricity.
A storm on the scale of the Carrington Event could damage the U.S. electrical grid to such an extent that vast regions of the country could be without power for weeks, perhaps months.
Without electricity, drinkable water would soon be in short supply, as would fuel, food, communications and just about everything else society depends on to function.
"The consequences would be almost incalculable," said Daniel Baker, director of the University of Colorado's laboratory for atmospheric and space physics.
An extreme solar storm hitting our modern, high-tech world would severely disrupt oil and gas supplies, emergency and government services, the banking and finance industry, and transportation. The cost of the damage could reach into the trillions of dollars, he said.
New electrical systems are designed to be efficient, which is different from being robust and hardened against the effects of a solar storm.
"There is an efficiency-vulnerability tradeoff," said George Mason University social scientist Todd LaPorte, who studies critical infrastructures. "Sometimes efficiency isn't your friend."
"Large storms can literally place millions of lives at risk," he said, and our growing dependence on technology is increasing that risk. "We should be preparing for a storm four to 10 times the intensity of the 1989 event (that blacked out Quebec). There is a false sense of security."
The reason the danger posed by space weather is not drawing more concern from the federal government, electric utilities or the public was summed up by David Crain of the space systems division of ITT, an engineering and technology company.
"The problem with space weather is nobody directly dies of space weather, and that is a detriment in getting funding and increasing public education," he said.
Unlike hurricanes or floods, the damage caused by solar storms is to underlying systems and not obvious in terms of visible devastation.
Preparing for extreme solar storms also involves spending millions, even billions, of dollars, and it is difficult to get the government to spend significant money to prepare for an event that is merely predicted, the speakers agreed.
"We have a hard time thinking about anticipation," said LaPorte. "We tend to react to events, not anticipate them. We're not good at heeding warnings."
"We have developed a new awareness of the extremes of severe geomagnetic storms," said John Kappenman, founder of Storm Analysis Consultants and an expert on the vulnerability of the power grid to solar storms.
Proposed designs for the grid may actually escalate the risk, he said. "There is an unrecognized, system-wide risk to the grid (from solar storms).... There is no design code to minimize this threat."
The scientists were assured by officials from the Obama Administration's Office of Science and Technology Policy that the threats of space weather are a concern.
But because solar storms do not result in immediate, visible damage, the participants at the forum said public education is critical to developing and implementing a plan to mitigate the damage from a future extreme solar storm.
"But if you do too much of that, what you end up with in the public is disaster fatigue," Crain said.