We had a hella storm come through the Twin Cities last night. Some hail, some wind, but piles of lightning. And then this happened in Dinkytown: Lightning struck a high power line, which fell across a couple of parked cars and stayed “live.” The live line heated up the pavement on the street enough that it caused a buried gas line to explode.

I’m pretty sure there are details we don’t know yet. Perhaps there was already a leak and the gas that caught on fire was already out of the pipe. Perhaps the lightning grounded through the gas line and that is what sparked the fire. Either way it totally freaked the fire department guys. They’ll be talking about this for a while!

Ever see anything like this before?

Details here.

Comments

  1. #1 Bob O`Bob
    May 6, 2012

    I would suspect that the power lines managed to induce fuel tank leakage, and significant fuel got onto the pavement before igniting. Tar-bound pavement can burn hot and deep, but it usually needs a little help getting started. Even just ounces of gasoline could do.

  2. #2 Greg Laden
    May 6, 2012

    It would be interesting to see if gasoline was involved, considering that there were cars burning up! But I think the main fire they were dealing with was natural gas from underground lines.

  3. #3 MadScientist
    May 6, 2012

    My guess is the gas line was already damaged but simply wasn’t ignited before. You’ve got to be pretty unlucky to have an ignition source right at a leak on a line.

    I’d like to know why the line stayed live though – maybe there just wasn’t enough current drawn through to trip the breaker or else the breaker was heavily iced up (in which case why didn’t the fuse pop when the breaker didn’t release).

    There was another incident I know of a week or so ago where a car took out an electric post and the wires stayed live – the gas tank also tore and the lines set the fuel ablaze. The folks in the car didn’t have a chance with the live car body and the fire.

  4. #4 Art
    May 8, 2012

    Likely either the gas line had an existing leak and the power line arc ignited the leak, or the power line attempted to ground itself through the gas line or fittings and it blew a hole in the line, then off to the races.

    It is possible to escape with a power line across the car body. The key here is that you don’t want to get between voltage potentials. In this case you either throw something non-conductive onto the ground and step from the car onto this, stop touching the car, then step onto the ground away from the car. Rubber floor mats, books, or the plastic interior door panels all might work. One slip or an inconveniently placed hole in your rubber mat means you die.

    The other option is to open the door and jump as far as you can. When you land you want to land in a ball and then stand with both feet together. To the extent possible you want to present yourself to any stray current as a single electrical point. If you land feet apart and the power is traveling through the earth any voltage difference will try to conduct leg-to-leg through your very conductive body.

    One variation would be to open the door and climb out on top of your vehicle without touching the ground. Then, once on top you make a running jump. Same rules about presenting a single point applies.

    If there is any possibility that the current is traveling through the ground and you are still in the field you keep feet tightly together and take tiny, one inch, steps moving away from danger. It takes time and you need to concentrate and maintain control, this at a time when every nerve ending is telling you to run, but it has been shown to work, mostly. This is considered standard emergency escape procedure. It doesn’t guarantee you live but it does tilt the odds in your favor.

    All this is based on a safety and emergency response training course I took a long time ago for crane and bucket truck operators, and people who work around high voltage power lines. They had us jump from the back of an old crane into a bed of sawdust, hit, roll as a ball, stand with feet together and baby step 20 yards to ‘safety’ on the other side of a red line. Everyone had to do it, and pass a written test, to get certified.

    Unfortunately very few people know this stuff and of those who do it is the oddball who maintains composure and awareness enough to use those procedures. One of the guys in my class learning this was in a situation and he panicked and ran. You can’t outrun electricity. He got internal electrical burns, nerve damage and scarring that had him out of work for half a year. Could have killed him. He said he knew in mid-stride that he shouldn’t have run and told himself, as we all do in the middle of an accident , when you come to yourself, Ohhh … sh … this is going to hurt… He woke up in the ER.

    He claimed to have a deep and profoundly intimate understanding of how frying bacon feels. Evidently human flesh badly burned by an electrical arc smells a lot like overcooked pork. Took him a while before he could look a BLT square in the eye.

    Contrary to popular belief the fuses and breakers used on power lines are all inverse-time units. They can carry several times their rated amperage for minutes. Only slightly overloaded they may stay live for hours. A lot depends on how good the ground path is. A low impedance ground path allows more current to flow and this makes the fuse jacks clear the line faster.

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