Timeline Of Warning Signs, Destruction, & Emergency Action During Merrimack Valley Gas Explosions

LAWRENCE (CBS) - Dozens of fires and explosions peppered the Merrimack Valley in the late afternoon of September 13, 2018.

Before that devastation, at the Columbia Gas monitoring center in Ohio, there were hints that something wasn't right.

4:04 PM: According to the NTSB report, Ohio monitoring center received a high-pressure alarm for the South Lawrence gas pressure system

4:05 PM: A second high-pressure alarm triggered in Ohio for the South Lawrence gas pressure system

4:06 PM: Columbia Gas controller reported event to the meters and regulations group in Lawrence

4:11 PM: First 911 call was made

4:30 PM: The affected regulator was shut down; an influx of gas had already flooded the system

4:52 PM: Fires and explosions were rampant, with state troopers, police and firefighters on scene at multiple suspected gas explosions

6:30 PM: Final fires extinguished

7:05 PM: Power turned off to North Andover, Andover, and Lawrence, to cut the threat of additional fires

7:42 PM: Two critical valves of the natural gas system finally shut down; Columbia gas technicians begin door-to-door gas shut-offs

September 14: Technicians complete door-to-door gas shut-offs