Firefighters in Lawrence, Massachusetts and surrounding areas responded to at least 70 natural gas fires or explosions Thursday. Electric power was cut to the area to prevent sparks that could set off more blazes and a general evacuation was announced. This is the most recent map of the fires published by state police:

MSP Fusion Center has current updated tally of responses to fires/explosions/investigations of gas odor at 70. Spread over wide swath of south #Lawrence and northern part of #NorthAndover with several others across Merrimack River in north Lawrence. pic.twitter.com/a7kBYaWFrJ

— Mass State Police (@MassStatePolice) September 13, 2018

Earlier, police indicated multiple neighborhoods were being evacuated:

Numerous evacuations of neighborhoods where there are gas odors are underway. Far too early to speculate on cause. Joint investigation will be conducted when situation is stabilized.

— Mass State Police (@MassStatePolice) September 13, 2018

Residents in the affected towns of Lawrence/North Andover/Andover who have gas service from Columbia Gas should evacuate their homes immediately if they have not already done so. Gas lines are currently being depressurized by the company it will take some time.

— Mass State Police (@MassStatePolice) September 13, 2018

As I was writing this, the Mayor of Lawrence requested that all residents leave the area:

Because of planned power shut down, Lawrence Mayor @danrivera01843 is asking ALL residents of South Lawrence to evacuate their homes.

— Mass State Police (@MassStatePolice) September 14, 2018

Obviously, with it getting later on the East Coast, there is a danger that people could go to sleep in houses that fill with gas overnight. Here’s what the evacuation order sounds like on the street:

#Lawrence NOW Evacuations being ordered @EagleTrib pic.twitter.com/Y7Fe0BFyWT

— Jill Harmacinski (@EagleTribJill) September 13, 2018

There are multiple videos showing some of the homes that have caught fire in the area:

#BREAKING#firefighters finally arrive at home in #Lawrence that is fully engulfed in flames following a gas line problem that led to multiple fires & explosions.#WBZ pic.twitter.com/5WMJAcQC93

— Scott Sullivan (@sullybunZ) September 13, 2018

#BREAKING: Mass State Police: MSP Watch center has confirmed response to 17 separate addresses for fire,explosion, or investigation to Lawrence/Andover/North Andover. (Video: @jliss1979)
pic.twitter.com/lhuanvQUrt

— I.E.N. (@BreakingIEN) September 13, 2018

Scene on Main St in North Andover pic.twitter.com/JfTBpgBt3E

— Joshua Miller (@jm_bos) September 13, 2018

It’s unclear how many people have been injured in the fires an explosions so far. It may be a few hours until authorities have a tally. As for what caused all of this, the consensus seems to be that it’s the result of a gas line pressure problem. The Boston Globe notes that some work on gas lines in the area had been announced earlier today:

The Columbia Gas website said in a posting dated Thursday, “We’ll be upgrading natural gas lines in neighborhoods across the state.” The site said that four projects were underway in Lawrence, four in Andover, and three in North Andover…

Overpressurization of gas lines has caused problems before. In November 2005, overpressurization of gas lines caused widespread gas leaks in Lexington, triggering the fiery destruction of one house, near explosions at seven others, and leaving hundreds without heat amid cold weather.

For now, the area is just trying to cope with an unplanned mass evacuation of tens of thousands of people on top of putting out dozens of fires.