Derecho Report: BGE Surprised by ‘Freak Storm’
'...no utility east of the Mississippi River could have anticipated the raw strength of this storm system.' —BGE report
The unpredictability of the June derecho was an important factor in the scope and length of power outages across BGE’s service area, according to a new report filed with the state.
BGE filed its Major Outage Event Report with the Public Service Commission on July 30 as is required by Maryland law after a "major outage event." The derecho, which hit on June 29, left more than three quarters of a million Maryland customers in the dark – 62 percent of BGE’s customer base in Maryland.
Focus on BGE's response intensified after a letter from Howard County Executive Ken Ulman and six other elected municipal heads. In it, they said BGE refused to give them specific outage information directly after the storm hit, and that the utility generally needed to improve its performance during severe weather events.
In its report, BGE stated that it “had no prior warning that a significant operational storm would be impacting BGE’s service area until approximately 10:30 p.m.; no request for crews was made by BGE at this time.”
“It is important to note that no utility east of the Mississippi River could have anticipated the raw strength of this storm system,” the report reads.
A head meteorologist at the National Weather Service (NWS) agreed.
“Forecasting convective storms … is one of the most difficult things to do,” according to Jim Lee, meteorologist in charge at the National Weather Service (NWS) in Sterling, W.V.
NWS forecasts about 20 to 25 severe thunderstorm watches a year, Lee said. Derechos are more like 4 or 5-year events in this region, and the storm that swept through Maryland on June 29, he said, “that’s more like once every two or three decades.”
On the morning of Friday, June 29, BGE scheduled calls with its weather service providers. According to the report, the two calls both yielded similar reports “low threat of thunderstorms for the evening, but not severe.”
NWS sent out a statement at 7:30 p.m. that Friday, warning damaging winds were likely in Howard and nearby counties.
“We didn’t have a lot of confidence at that time” that the storm would hit the area, Lee said, because at that time, the storm still had not crossed the Appalachian Mountains.
The mountains are a crucial landscape when it comes to forecasting large-scale wind storms in the Mid-Atlantic, Lee said. Typically, “as soon as they hit the Appalachian Mountains, they fall apart.”
In addition, he said, at about 6:30 p.m. Friday, the squall line–or line of severe storms–was still in Ohio and looked like it would be heading south and west of Washington.
“By 9:30 p.m., we were getting a lot more confident,” Lee said. NWS issued a special weather statement at 9:35 p.m. that advised an “extremely dangerous thunderstorm” would impact the Baltimore-Washington area.
A storm watch (which means conditions are favorable for a storm) was issued at 9:51 p.m. for Howard, Carroll, Baltimore, Harford and Anne Arundel counties.
The goal at NWS is a 17-minute lead-time for severe thunderstorm watches.
“In this event we gave over 37 minutes of lead-time," said Lee. "From a forecasting standpoint, that’s very good.”
In its report, BGE also noted that it was not until about 10:30 p.m. that “the full strength and destructive nature of the storm was known.” The utility had, the report said, taken steps earlier in the day to “pre-mobilize additional crews to respond to potential heat-related outages and what was anticipated to be normal thunderstom activity.”
But the derecho was not “normal thunderstorm activity.” It was, in the words of the report, “one of the most destructive storms in BGE’s nearly 200-year history.”
“It was a freak storm,” Lee said. “The state of the science doesn’t allow us to say ‘Hey, BGE, hey PEPCO, in 10 hours we’re going to have a derecho.' The science isn’t there yet. We would love it to be. But it isn’t.”
Read Patch's coverage of the derecho and its aftermath: