Weather Service keeps special watch on the Key Bridge to help the collapse response effort

Conditions were calm and clear Monday morning, when several tugboats finally pulled the Dali container ship from where it struck the Francis Scott Key Bridge, destroying the span March 26, and moved it back to the Port of Baltimore.

The weather was a stroke of good luck, after rainy and stormy conditions twice delayed the coordinated explosions that largely freed the ship from the bridge piece pinning it in the Patapsco River.

“We are extremely grateful that the weather was excellent today, because it just made for better working conditions for all of the salvors out there,” said Nick Ameen, a spokesman for the joint-agency Key Bridge response effort.

Perhaps the only thing that could have delayed the refloating operation would have been lightning in the area, Ameen said. Thanks to meteorologists who have been assisting the salvage effort, they knew they were in the clear.

Since the day the Key Bridge collapsed, the National Weather Service has been providing hourly forecasts specifically for the bridge site with a dedicated webpage launched specifically for the response effort.

The weather service also provides four weather briefings per day to the Key Bridge recovery team, in addition to a weekly briefing every Saturday, said Chris Strong, warning coordination meteorologist at the weather service’s forecast office for Baltimore, located in Sterling, Virginia.

“It’s just such a complex operation with the cranes, with the people in the water, all the boats that are out, people working in very difficult — potentially dangerous — situations,” Strong said. “Knowing as accurately as they can, what’s going in the atmosphere, what’s going on in the water — and the interface between — is really paramount.”

The weather data is a critical part of each day at the Key Bridge Unified Command Center, headquartered at the Maryland Cruise Terminal in Baltimore Peninsula, Ameen said.

“Every morning at 8 a.m., throughout the duration of this response effort, we’ve had a daily morning situation briefing. And one of the key slides that is presented during that briefing is solely focused on weather, because it plays such a big factor into salvage operations,” Ameen said.

That fact was clearly on display earlier this month as crews prepared for the explosive demolition to remove the bridge trusses laying across the bow of the Dali freighter.

On Mother’s Day, when officials had “really hoped” to complete the detonations, nearby lightning strikes delayed the operation too far into the day, Ameen said. The detonation needed to take place during low tide, so the ship would stay relatively still after it was freed. The detonation ultimately occurred the next day.

With the extensive cleanup operation well into its second month, officials have reported no injuries to members of that crew.

The National Weather Service has used similar pages in response to other disaster recovery efforts, Strong said, including the Deepwater Horizon oil spill in 2010. The weather service team in Sterling also has used special forecast webpages for inauguration and Independence Day festivities in Washington, D.C., Strong said.

“Early in my career, back in 9/11, we provided similar support to the Pentagon response,” Strong said. “It was more faxing, and less webpage-based.”

Since the webpage debuted, the weather service has refined it to include the most pertinent measurements to the cleanup crews, whether they are suspended on cranes cutting apart a bridge piece, diving into the Patapsco, or standing on a barge, Strong said.

“For example, the cranes they were utilizing had a threshold for 20 knots of wind or higher, so that’s one of the thresholds we were using,” Strong said.

The webpage is color-coded, with weather threats characterized from “none” to “extreme.” It includes metrics like heat index, cloud cover, the percentage change of precipitation, and visibility. The page also includes information on water temperatures, tides and currents.

The weather service uses several nearby weather stations to assess the conditions at the Key Bridge site, Strong said, including one on a concrete platform in the Patapsco River, about 250 yards from where the Key Bridge once stood, that survived the bridge collapse. Operated by the National Oceanic and Atmospheric Administration, it dispatches real-time data on wind speeds and air temperature to the National Weather Service.

Others are located in the channel near Baltimore’s Curtis Bay and near the mouth of the Patapsco River.

NOAA did lose two pieces of meteorological equipment that had been on the bridge, said Christopher DiVeglio, maritime services program manager for the administration’s National Ocean Service.

The first was an “air gap” system that measured the distance between the bottom of the Key Bridge and the surface of the water — a critical measurement for the massive ships like the Dali that passed beneath the bridge as the tides rose and fell. Also lost when the bridge collapsed was a weather station on the northeast tower, which collected data on wind speeds, air temperature and air pressure, DiVeglio said.

As part of the response to the collapse, the National Ocean Service installed a special buoy for measuring the river’s current in the days following the collapse, DiVeglio said. It’s “affectionately known as CURBY,” or Currents Real-time Buoy, he said.

Anchored to the river bottom, the buoy’s platform looks similar to a yellow car tire, atop which sit solar panels, antennas and meteorological equipment. A meter that assesses currents is affixed under the platform, where it assesses the water column below.

“The currents, they’re not overly strong in that area,” DiVeglio said. “What we have seen is there’s a lot of shear … so in the top part of the water column, you might have currents that are moving in one direction, but then further down in the water column you might have them moving in different directions.”

That can stir up sediment and debris, making the water more turbid for salvage divers in the Patapsco, DiVeglio said.

After the salvage operation is complete and a new bridge rises on the Patapsco, it likely will carry much of the same weather equipment as its predecessor, DiVeglio said.

“At least in the conversations that I’ve had, there’s very strong interest in outfitting a new bridge structure with these tools, that certainly have helped mariners transit safely and efficiently,” DiVeglio said.