It happened in a flash: Lightning lit up the southern sky, strobing back-and-forth next to the Jefferson Memorial while the Tidal Basin’s calm water reflected the dancing bolts.
A crowd of tourists gathered at the Martin Luther King Jr. Memorial erupted into cheers after the lightning flash ended. Their view across the open water was near-perfect.
But the lightning flash was much bigger than what was visible to the cheering tourists. It originated 8.7 miles above Earth and spanned a distance of 15.5 miles, from the Potomac River near the Woodrow Wilson Bridge to east of Andrews Air Force Base. Much of the flash was concealed by storm clouds, however, which is what happens with most lightning flashes, particularly in the Mid-Atlantic region.
At the time of the lightning flash, I was at the Tidal Basin recording video on my Sony a99II DSLR camera. I was just east of the MLK Memorial, relaxing on a park bench with my camera and tripod positioned in front of me, close to the water.
A storm was developing to the south of Washington, and it had produced no lightning or thunder, but it did have a couple of cool, slanted rain shafts so I thought it might look good in a time-lapse video. I started my camera in movie mode and recorded the storm for about three minutes before the flash occurred. The flash itself lasted only two-tenths of a second.
The brilliant burst of lightning was a surprise, appearing in a sky unobstructed by rain or low clouds. There was no wind at the time of the flash, and the bolts of lightning reflected well on the surface of the water. It was the first lightning flash I observed from the storm, and it was a good one.
About 24 seconds after the flash, which I confirmed with my video clip, rolling thunder was heard. Given the five-second-per-mile rule for lightning and thunder, the lightning occurred about five miles away.
Mapping the storm in 2-D and 3-D
After I returned home, I contacted Scott Rudlosky, scientist at the National Oceanic and Atmospheric Administration, to research the size and location of the flash using data from the D.C. Lightning Mapping Array (DCLMA).
The DCLMA consists of sensors that monitor very high frequency radio waves emitted by lightning. The data can be used to display lightning in three dimensions. The goal of the DCLMA is to provide detailed insights into the structure and evolution of convective storms to help with forecasting severe weather.
Rudlosky put me in touch with Mason Quick, lightning scientist at the University of Maryland. Quick used the time stamp from my video file to locate the lightning flash in the DCLMA data.
According to Quick, the lightning flash produced 709 impulses at altitudes ranging from 1.2 to 8.7 miles (2 to 14 kilometers) above Earth. The flash extended nearly 15.5 miles (25 kilometers) from west to east, stretching from the Potomac River to east of Andrews Air Force Base.
Quick then created three-dimensional and two-dimensional imagery of the flash, shown above and below.
Regarding lightning safety, I would not have chosen that particular location on the Tidal Basin to shoot video with an approaching thunderstorm. At the time, there was no thunder and lightning, and the storm was moving to the east, away from the area.
A small rain shower developed overhead, however, which lasted a few minutes, and that did worry me. Thunderstorms that develop overhead can be the most troubling, but no lightning was produced by the brief shower.
The thunderstorm and the rain shower moved quickly to the east, and the time-lapse video shows the only lightning I witnessed during my shoot that evening in D.C.
Below, I share a time-lapse video and still images of lightning pulled from the video frames.
Time-lapse video of the thunderstorm, May 30. Ten minutes and 40 seconds of video were compressed into 16 seconds. (Kevin Ambrose)