UPDATED (2:12 p.m.)—The unpredictability of the June derecho was an important factor in the scope and length of power outages across service area of Baltimore Gas and Electric (BGE), 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.

More than 100,000 BGE customers in Anne Arundel County lost power in June in the days after the storm.

The investigation was initiated by a letter sent by Howard County Executive Ken Ulman and six other elected municipal heads, including Anne Arundel County Executive John Leopold. 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.

BGE stated in the report that it “had no prior warning that a significant operational storm would be impacting BGE’s service area until approximately 10:30 PM; no request for crews was made by BGE at this time.”

Furthermore, BGE said that other utility companies also did not expect the storm to be so severe.

“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 NWS in Sterling, WV. 

On the morning of 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.”

A storm watch—which means conditions are favorable for a storm—was issued at 9:51 p.m. that day for Howard, Carroll, Baltimore, Harford and Anne Arundel counties. The goal at NWS is a 17-minute lead-time for severe thunderstorm watches.

"We want to be able to provide you 17 minutes," Lee said. "So that you can seek shelter, go outside and roll up the windows, put your deck furniture away and bring your kids inside. 

“In this event we gave over 37 minutes of lead-time. From a forecasting standpoint, that’s very good.”

BGE noted in its report 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. 

See more:

• Derecho Storm Left ‘Hurricane-Like Damage’
• POLL: Tell Us About Your Power Outage Experience
• WATCH: Devastating Derecho in Action
• VIDEO: BGE Works to Restore Power
• Attorney General Gets Reports of Price Gouging After Storm
• UPDATE: BGE Making Progress in Restoring Power
• UPDATE: Storm Leaves Power Outages, Fallen Trees in County