[spdustin]

For my kids, I have a virtual light switch in HomeKit called "Shower Is Safe". It's pinned to the top of the Home app.

I use the Home Assistant integration to fetch this data and run some calculations on the past few minutes of lightning activity. Since the API returns lightning strike time and bearing from a given location, I can (in combination with wind direction) determine if the lightning is approaching or receding.

If it's approaching and less than 30 minutes away (or if any strike is within 20 miles in any direction), it turns off the light switch. It then waits until it's been receding for at least 15 minutes (and with no more detections within 20 miles) before switching "Shower is Safe" back on.

I can (and do) override it if I notice it's potentially hazardous to shower.

[Dibby053]

I don't want to frighten your family more, but shower NEVER is safe. Unlike lightning, slips and falls in the bathroom are quite common and sometimes result in death or lifelong injury.

[iamthejuan]

Smaller bathroom will resolve this to avoid total fall to the ground.

[purplerabbit]

Sponge bath lying down in insulated closet is safest option

[readyplayernull]

Even better, there is a way to avoid every risk and save water...

[lucioperca]

Let me tell you about the flesh-eating bacteria living in your sponge. You better microwave it beforehand.

[steadfastbeef]

I've heard in California that will cause cancer.

[jajko]

good that our ancestors didn't know about all this, they would just kill themselves right away sparing us all these enlightening discussions

[k8sToGo]

There is a chocking hazard with the sponge.

[diggan]

Attach it to a 10cm long string with something wide at the other end, so in the event of accidentally swallowing it (and ignoring the "why/how"), you can just pull it out. Problem solved.

[maicro]

Just make sure to not leave it in the driveway and it'll be fine.

[kzrdude]

I would guess the kind where you shower standing in a bathtub are much more risky than just a plain flat floor shower?

[imp0cat]

IKEA Patrull (the green crocodille bathtub mat) is the easiest solution.

[spdustin]

Nobody's frightened. We enjoy the storms. :)

[phoronixrly]

Wait, why would showering in a lightning storm not be safe? Do you expect the lightning to discharge in the pipes of your house? How?

Or is it that your children would be scared if the power goes out when they're showering? That I understand.

[spdustin]

Yes, especially in older homes or homes with poor grounding. Lightning can discharge through water supply lines[0]. There are even cases of toilets exploding due to lightning strikes[1]. (Google for more)

Sure, it's exceedingly rare. But it's also exceedingly easy to avoid. I've taught my kids that some decisions are easier when defined as binary rules; judgment calls in cases like this just don't offer any tangible benefit other than "I showered an hour earlier than I would have otherwise."

[0]: https://www.weather.gov/safety/lightning-indoors

[1]: https://fox8.com/news/lightning-blows-up-toilet-after-travel...

MythBusters even did a bit on it. They rated it "plausible".

[lxgr]

On the other hand, I wonder if you might be teaching a bad lesson about neglect of probability [1] here. The shower itself is probably orders of magnitude more dangerous by itself.

I'm wondering because I am also unsure myself if I should be concerned about lightning when showering, or whether it's statistically speaking an absolute waste of time :)

[1] https://en.wikipedia.org/wiki/Neglect_of_probability

[KeplerBoy]

It really depends on your housing situation.

If you live in the lone, old house on a barren hilltop that gets struck by lightning on a weekly basis, I wouldn't take my chances with showering during the storm either.

[lucioperca]

Install this, instead of a light in the bathroom: https://en.wikipedia.org/wiki/Lightning_rod

[mschuster91]

In a lightning strike, electricity doesn't exclusively follow the lightning rod. That's the problem.

The major part of the current will flow through the rod, but a small remainder can and will cross into the house - TV/radio/sat antennae and overhead electric/phone wires are the main culprits here, but belowground cables and water/gas/metal sewer pipes can also serve as a point of ingress.

Normally you're supposed to have proper grounding at each of these ingress points as well as surge protectors, but all it takes is for one of the grounding connections to be a tad bit loose or a SPD being expired due to prior overvoltage events, and suddenly the pipes or whatever can pose a significant enough voltage differential to the rest of the house to kill you.

And if that news isn't bad enough, most people (especially landlords) do not care too much about their electrical and other wiring in the home. Every few years you should re-tighten wire connector screws with a torque wrench to make sure the connections are still up to the spec of the manufacturer, and grounding rods need to be regularly measured as well, particularly after drought periods to make sure they haven't dried out in the time since the last check/construction.

[spdustin]

The difference in expected utility from showering (either during a lightning storm or not) is minimally affected by the choice to postpone it. That's why I'm content to call it a binary rule.

The choice of showering/bathing at all has a different risk profile, yes, and also a different expected utility. Comparing the two is a false equivalence.

Statistically speaking: our kids (and their parents) simply enjoy watching storms, and we all choose to shower when the risk of lightning is zero. That choice maximizes utility, as our subjective enjoyment of the light show isn't diminished by postponing something as pedestrian as a shower for an hour.

[lucioperca]

You could improve the grounding instead of spending time making such a light.

[dekhn]

I have not found that arguing with lightning-is-death folks to be particularly successful.

[imp0cat]

That is easier said than done, especially in an old house.

[sadcherry]

Do you have any statistics about lightning-related injuries or deaths in showers?

[wickedsight]

I had to look it up, because this seems like a pretty unrealistic fear to me. What I fond:

> less than 1 in 1 million chance of being struck by lightning directly or indirectly

> One-third of all lightning injuries occur indoors.

I'm pretty terrible at statistics, but I think we can assume that there's a less than 1 in 3 million chance to be injured by lightning indoors.

But lightning related injuries indoors could also be from a window exploding after lightning hits a tree outside, or a fire related injury from a lightning strike to the house.

So what's the chance of being hit by lightning in the shower? And then being seriously injured?

Snopes lists 4 examples of people being hit by lightning in the shower, spread over 20 years. All of them with minor injuries. The chance of major injuries is also much lower than with a direct lightning strike.

So finally, is the 'safe to shower' thing useful? I'd say that making this is probably time that could've been spent on more useful safety related things.

Also, if it's just 'is it safe to shower?', it ignores tons of other dangers inside the house during thunder storms. Touching any tap, corded appliance, concrete wall or floor or being near an outlet is just as dangerous as being in the shower and none of those things are particularly dangerous in the grand scheme of things!

[danbruc]

This [1] is the best I could find with a quick search, admittedly far from ideal, but it has some numbers to start with and might help to locate better data.

[1] https://www.independent.co.uk/news/science/it-safe-take-show...

[optymizer]

I don't know about this approach. Seems a bit panicky / heavy-handed to turn this particular risk into a "judgment call" compared to all the other risky things kids do. Could just be an occasional conversation / reminder:

- "We can't take a bath / shower right now. There's a big lightning storm outside." - "Why not?" - "The lightning hits the ground and it can spread through the water. It's not safe." - "OK"

Is it really worth teaching kids to check this signal every day, instead of having this conversation like twice a year?

If the kids had to check multiple things before showering, this light would simplify the decision making process, but by the sound of it, it's redundant.

If it's unsafe enough not to shower, you'll probably hear the thunder too. There's your signal not to shower.

Though maybe it's not like that and the kids enjoy it.

[spdustin]

It storms a lot here. And kids are notorious for not hearing things that are obvious to the rest of us. :)

My kids aren't paranoid, they don't freak out about the storms. It's just a natural thing, and a reminder that there's a potential that nature's best light show is in store for them. A nice side effect is that they're not afraid of storms—they look forward to watching them.

[phoronixrly]

Ok, blanket advice from US governmental agencies and a Mythbusters episode with electrical and water installations that seem... Very DIY and not up to code? I mean it is mythbusters... IDK.

I suspect power outage in the shower is more dangerous in my case than any other electrical issue... I guess it may be more of a US issue, especially since I am not finding any advice from EU agencies on the matter?...

[spdustin]

Building are different in different countries, and other geopolitical divisions. The UK authorities, for example, say it's safe to shower during a storm as long as your plumbing has been properly integrated into a standards-compliant equipotential bonding, noting that said standards change over time. So, you'd have to know them and trust/verify the builder followed them.

Or, you know, just wait a while and enjoy the show.

Whatever. You do you.

[Spivak]

But is there any risk to you being in the path of least resistance? All your pipes are connected (to the ground) so why would the electricity not take the readily available metal path?

[spdustin]

The risk of death of showering during a lightning storm could be the same as the risk of death going for a 15 mile drive[0].

A typical lightning bolt is about 300 million Volts and about 30,000 Amps. Since even the best-grounded home certainly can't sink 30,000 amps of current into the neutral-bonded earth bar, it has to go somewhere. It finds multiple paths, and the current is shared between them. There's also the conversion to heat in all those insufficient conductors, etc.

[0]:https://www.independent.co.uk/news/science/is-it-safe-to-tak...

[icehawk]

Electricity doesn't only take the path of least resistance, it takes all paths available in inverse proportion to their resistance (impedance really.)

And since the water and sewage systems are plumbing systems and not electrical systems, its highly likely they'd be at different electrical potentials in a strike.

[therein]

I think they don't trust the grounding or the house doesn't have proper grounding.

Either way should be easy to test. Run the showers and excite the paratoner.

[spdustin]

I learned long ago not to trust corporate homebuilders.

[atoav]

Lightning strikes can induce significant current flows within all conducting parts of a building. This is obviously worse with parts that are not (or not well) grounded.

Basically without a lightning protection system you could stand next to a power outlet and a spark could bridge over to you and flow into the ground (there are slomo videos of such things happening in specific tests that have been conducted).

I think the shower warning app is a bit overkill. If your place is that frequently hit by lightning strikes I'd install a proper lightning protection system with a narrow mesh width and surge protection devices in all sections of the house. Yeah and ground that shower.

The hardest part about retrofitting such a system is getting a decent/low impedance ground connection. Ideally you'd embedded a steel mesh into the fundament and connect it to the lightning protection system on all sides. This is kinda hard if a house is already there, so digging deep on the sides of the house and trying to get connections under it (if possible) is the next alternative.

In any case make sure that ground impedance is actually measured..

[telgareith]

Lightning has reached down from 10,000ft to strike the ground, do not make the mistake that it cares about anything humanity has built. Even with a lightning rod/abatement system, its probabilities and 'preferred paths.'

Plus, we really don't know all that much about lightning. Things like "ball lightning" (https://en.m.wikipedia.org/wiki/Ball_lightning) seem insane/impossible, but theres too many reports from everywhere on earth that go back hundreds of years- enough of them from reliable sources that its just "unexplained."

[zikzak]

My father was born in 1930 and shared a bed with two siblings around ages 5-8. The bedroom was a small room at the top of the house and was on the wall where the electrical supply attached to the house from the street.

During a bad storm one night, they heard a buzzing sound at the window by their bed and saw an intense light outside. The ball lightning then entered their room at the window (I have no idea how that would work) and followed the wall out to the hallway. The whole time, they could hear a sizzling noise and the light was blinding.

Where it had entered the room, there was a fire outside where the electrical supply connected the house that entered the room. They took off out the door and down the the stairs. The fire damaged their house but did not spread (they think the rain put it out).

I have also heard that there was a family that had ball lightning enter their house down the wood stove chimney and emerge into their kitchen, followed the wall around the room, and the fizzled out.

Both incidents were a very long time ago. Other than that, I don't know anyone who has seen this phenomenon personally (my father passed away a couple of years ago).

[telgareith]

Nobody knows. It's why it's so interesting, and controversial.

"Two children and fire? Ball lightning... I've never heard matches called that before..."

But then somebody stops and thinks... How would they know about Ball lightning at that age, in that age.

Repeat that with thousands of accounts across cultures, continents, and at least 500 years. It's a real humdinger. Descriptions of Ball lightning are, afaik, more consistent than how people of different cultures handle psych problems.

I find it comforting to know there's so much more about the world to explore.

[ripped_britches]

There’s no risk if your water supply lines are pex instead of copper

[telgareith]

Yea, because water is an amazing insulator. /s

[adrianN]

Water is a reasonably good insulator actually. You need a lot of dissolved minerals to make it a good conductor.

https://m.youtube.com/watch?v=dcrY59nGxBg

[AhriSafari]

I learned a few months ago showering in lightning is dangerous.

[phoronixrly]

You can't just say that without explaining why.

I live on the 8/10 floor of a building that gets yearly lightning rod inspections. All piping has been replaced with polypropylene (clean water) or PVC (dirty) and even when it was metal, the electrical and water systems were far apart from one another. Even if they were not far apart, all wiring is underground. The transformer is inside a nearby building and also has lightning rods/wires and all wiring to and from it is underground. There is literally no scenario apart from ball lightning coming through my bathroom window while I shower that I can think of

[mschuster91]

> I live on the 8/10 floor of a building that gets yearly lightning rod inspections.

That puts you in a very exclusive community. Most landlords don't bother to do anything that's not required by code/law.

[refibrillator]

Nice, what are the odds though? I searched around but couldn’t find any hard stats.

Is this like nuclear bunker in my basement type of precaution?

[spdustin]

Yes, it's exceedingly rare. But it's one of those "avoiding this activity for an hour could prevent you from dying painfully" things, so we don't shower/bathe/wash dishes when there's lightning.

[lxgr]

> it's one of those "avoiding this activity for an hour could prevent you from dying painfully" things

If you do this often enough, for extremely unlikely scenarios that don't sum up to a meaningful aggregate risk of dying, you might very well have a negative return on investment though. (Time spent worrying about an unlikely sudden death is time you don't spend enjoying life, or at least avoiding a slightly earlier but much more likely death.)

[spdustin]

As mentioned before, we don't worry. There's no judgment. It's a simple binary. And we spend the time enjoying the storm that we otherwise would've missed.

[eth0up]

As a Floridian not far from a lightning belt world capital, I also never shower (or wash) when lightning is expected. I remember seeing a photograph of a car with a giant orifice where the hood and window were. Extremely rare, faraday and all, but I've seen some strikes that dignify paranoia and know several people who've lost family to lightning.

I'm more primitive in my safety measures, but that's a pretty cool system you have.

Edit: I also unplug my valuable electronics too, if I'm able. And yes, I've seen all sorts of stuff toasted, from cows to computers.

[pdntspa]

Are you ensuring against any other black swan catastrophes or just this one?

[octopoc]

For bonus points if the shower becomes unsafe while in use, you can optimize the shower by turning off hot water using this gadget: https://faucetlist.com/collections/thermostatic-shower-fauce...

[mercwear]

What other automations do you have? This one seems so specific I am curious what else you have going on!

[spdustin]

A similar one changes my LED-filled floor lamp (running WLED) to a pattern that matches the current weather conditions. Falling rain, lightning, heat "rising". Sort of an ambient notification system.

Another warns my wife if her commute time home is expected to be longer than usual, so she can opt to get a bit more work done if it means a quicker drive with a similar arrival time.

My favorite is the laundry notification. Current sensing outlets let us know when the washer or dryer is in use, and door sensors track if the lid to the washer or dryer is open/closed. So if someone starts laundry, the HomePods play a chime and announcement that "the washing machine is done!" If the door isn't opened in 15 minutes, it chimes again. Another 15 minutes, and a notification is sent to me and my wife. :D

[mercwear]

Nice! The washing machine done alert is a great idea, I may steal that one =-)

[j_bum]

Would you be willing to explain/share the automation for this?

[spdustin]

It largely centers on this template sensor:

    {% set distance = states('sensor.lightning_detector_lightning_distance')|int(999) %}
    {% set bearing = states('sensor.lightning_detector_lightning_azimuth')|int %}
    {% set wind_bearing = states('sensor.pirateweather_wind_bearing')|int %}
    
    {% set bearing_normalized = bearing % 360 + 360 %}
    {% set bearing_left = (wind_bearing-80) % 360 + 360 %}
    {% set bearing_right = (wind_bearing+80) % 360 + 360 %}
    {% set distance_max = 20 %}
    {% set bearing_min = ([bearing_left,bearing_right]|sort)[0] %}
    {% set bearing_max = ([bearing_left,bearing_right]|sort)[-1] %}
    {% set approaching = bearing_min < bearing < bearing_max %}
    {% set close = distance < distance_max %}
    {{ close and approaching }}

It normalizes the bearings to avoid dealing with the 0-degree crossover, and is reevaluated automatically whenever the three tracked entities change their state.

The automation itself is set to "restart" mode, and fires whenever the template sensor is true. It then waits for the sensor to be false for 15 minutes, and for the nearest lightning distance to be > 20 miles for 15 minutes.

Why a 20 mile radius? It's a good enough proxy for the time it takes them to prep for (get clothes ready, etc) and then actually shower (and brush teeth, 30 minutes total), and most storms in my area tend to move through at ~40mph.