June 25, 2010 — A brief, explosive thunderstorm that struck Charlottesville during Thursday's rush hour littered areas of the University of Virginia's Grounds with downed trees and limbs, disrupted power supplies, snarled traffic and caused minor building damage – but amazingly caused only superficial injuries at the University.

"Thank goodness it's just landscape," said Rich Hopkins, landscape supervisor for U.Va.'s Facilities Management Division. "We can always grow things back."

There was no immediate dollar estimate of the storm damage, said Donald Sundgren, chief facilities officer.

By Friday afternoon, the most vexing problem was restoring full power – particularly to the Health System, which was functioning on emergency power, forcing the cancellation of many outpatient appointments and postponement of elective surgeries.

Cheryl Gomez, director of energy and utilities at Facilities Management, explained that one of the University's main substations lost two of its three supply lines from Dominion Power. The University can function fully with power from any two; with just one, power had to be cut to several University buildings to ensure an adequate supply to the Health System and medical research facilities, she said.

Dominion hoped to have all three lines restored to the substation by 3 p.m. Friday, she said, noting that Dominion had called in out-of-town crews to help restore full power to the Medical Center.

Meanwhile, several other University buildings served directly by Dominion were also without power, including Carruthers Hall, which lies in one of the hardest-hit areas of the storm, near Barracks Road. Carruthers – which houses the servers that host the University's home page and e-mail service – also had trouble with its backup generators, leaving much of the University with no e-mail and spotty Internet access.

Dominion reported that 45,000 customers were without power at the peak of the outages. By Friday afternoon, about a third were still in the dark.

The problems started Thursday when the temperatures climbed to record levels – 100 degrees at the McCormick Observatory – said Jerry Stenger of U.Va.'s Climatology Office. With the dewpoint also high, trouble was coming, he said.

"When you have that kind of heat and humidity, you are very likely to have thunderstorms pop up and become quite strong," he said.

That's what happened around 5 p.m. Though there were no signs of tornados, there were likely "downburst winds" – blasts of air that descend at high speed, then hit the ground, accelerate and fan out. The winds can easily equal those of a weak tornado, he said.

"Its not unusual to see tornado-scale damage from these winds," he said.

One of the highest reported gusts in Virginia was clocked at 58 mph near the Shenandoah Valley town of Strasburg. "It seems very likely that there were wind gusts in excess of that, but not in an area where measurements could be taken," Stenger said.

The winds wreaked havoc with trees all over Charlottesville, and the University was no exception. North Grounds was particularly hard-hit, with some trees uprooted and others losing their tops, Hopkins said.

Some University buildings suffered some roof damage, most significantly at Carruthers, Clark and Saunders halls, said Jay Klingel, director of operations and maintenance at Facilities Management. The U.Va. Art Museum and Zehmer Hall also suffered some damage, with minor damage to a few other buildings.

On Central Grounds, tree limbs – some up to 18 inches in diameter – were strewn around. Amazingly, there were no reports of injuries or damage to the Academical Village, apart from some damage to the serpentine walls. An evergreen limb took out a 25-foot section of one wall in the alley between Pavilions I and III.

There were also reports of damage to cars parked in some University lots.

At midday Friday, limbs were piled along McCormick Road and major sidewalks, awaiting pickup by Facilities Management crews. The whine of leaf blowers could be heard sporadically.

Everyone seemed to have a storm story.

Gomez, the energy and utilities director, said she was walking back to Facilities Management from a meeting at the Rotunda when the storm hit. Soaked to the skin and unaware of the widespread damage, she decided to drive home to change into dry clothing.

It took more than 45 minutes to negotiate the three miles to her house, she said. She promptly returned to her office, where she worked until after midnight. She was back in around 5 a.m. on Friday – while others in her office worked through the night, she said.

"It was an amazing storm," she marveled.