Thunder Storm advice from a forecaster with the NWS

[Catrin]

The following information was posted to the Surly LHT owners email list by a forecaster with the National Weather Service. I am posting this here with his permission.
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"When thunder roars go indooors" just
doesn't woork for those of us on long bike rides, hikes, etc.

The NWS has also thrown out the 6 mile rule. Really if you can hear
thunder, you are in danger. To measure lightning distance, use the
fact that the speed of sound is roughly 1000ft/sec. Measure time
between flash and boom, then divide by 5 to get miles.

But better than this, be situationally aware. Get a forecast before
you go out, especially if you will be out for many hours or days. I
think you will be hard pressed to beat the day to day forecasts from
the NWS http://www.weather.gov/ Click on the map to get your local
office. Then you can click on their map to get your local area. There
is a different forecast for every 2.5km or 5 km, depending on the
office.

But when you are out, keep watching the sky.
It takes 3 ingredients to build thunderstorms: lift, instability, and
moisture. Lift can be produced by mountains, cold fronts, differential
heating, or in Florida's case sea breezes.

As for moisture and instability, watch the sky for any cloud that has
vertical growth, especially in the morning:
cumulus http://www.usatoday.com/weather/wcumulus.htm
altocumulus castellanous (ACCAS) http://tinyurl.com/23xmvmk
cirrocumulus http://mmem.spschools.org/grade5scie...rocumulus.html
If you see the cumulus, towering cumulus, or ACCAS before 11 AM,
chances are you have sufficient moisture and instability for afternoon
thunderstorms.
Adjust your behavior with that in mind.

And you don't have to be underneath a thunderstorm to get struck by
lightning. Lightning bolts off the sides or tops of thunderstorms can
strike many miles away from the base and are some of the most powerful
lightning stikes.

The NWS recommends that if you can hear thunder, you are in danger.
And the 30 rule says, stay under shelter until 30 minutes after you
last hear thunder. I can say that if I followed that rule, I wouldn't
be out for most summer afternoons or early evenings. Lightning safety
is about risk analysis and informed choices. To be perfectly safe, you
need to very carefully sit on your couch. Of course there are many
risks associated with that behavior too!

[bmccasland]

You mean like don't be out in a boat on the water when you see zots of lightening and hear thunderclaps like I did last week? I may get paid to go boating, but they don't pay me enough to get zapped by lightening. And being in an aluminum boat didn't make it OK either.

[TrekTheKaty]

This is great advice. Right after I got my iphone, we were out for a ride. A pop-up line was very visible, so we pulled off the Katy Trail at the Defiance Bike Shop and took shelter--ie, petted the cats, jersey shopped and ate ice cream. I got out my iphone and pulled up the local radar to confirm it was an isolated shower. My sis was floored--technology!

[NoNo]

This is the exact reason we cut our century attempt short on Sunday. They were calling for storms throughout the day, with the worst ones coming sometime around when we'd be finishing up. You know what? No ride is worth taking that risk. So we took the 50 mile route, rode through some rain early on, and finished before the nasty stuff moved in. There will always be another day to ride.

[lauraelmore1033]

Oh dear,
last year I was on an organized ride during a thunderstorm. I was sure people would start looking for cover, but they all continued on as if nothing were happening. I asked a guy if we should maybe consider getting out of the storm and his reply was something to the effect that: he would be fine since his bike was full carbon--everybody else could do what they liked. I just kept going, figuring that there must not be any danger and besides, there were plenty of really tall people in the field that would likely get struck first, but in hind sight, that seems pretty daft. Luckily, no one was hurt, but I guess we could have been??

[NoNo]

I should add that as someone who was struck by lightning through the phone (mom was calling to tell us to unplug the tv - too late), I don't mess with storms. Are the odds in your favor that nothing will happen? Sure, but why even tempt fate? When there's a storm, I stay inside, and avoid using the shower or phone. Don't have to tell me twice!

[MartianDestiny]

Honestly, I didn't find that very helpful.

Yea, "stay inside", etc. I get it, great lawyeresse, and not bad advice either if a storm is eminent. (but not particularly new or novel advice...)

Frankly though, if I sat on my rear on the couch every time there was a "chance of scattered thunderstorms" I would NEVER go outside during the spring/summer/fall (MONTHS at a time) and 80-90% of the time it never even rains on those days; though it will cloud over for a few hours or maybe I'll see the storm in the distance.

Much better to advise people on what to do if they find themselves "stuck". Where to go, where not to go. What's relatively safe, what isn't. When it may be better to keep going and when you should definitely seek out a safer area to stay put. You can do enough, even in the middle of nowhere, to reduce your lightening strike risk to even nearer nill than it already is, but they don't mention any of that. And when you live somewhere where afternoon thunderstorms are regular events THAT'S the information you need, because they'll pop up out of clear blue sky in a matter of minutes and there's not a darn thing you can do about it. (no, I'm not exaggerating)

People need to be smart, informed, proactive about the weather, not necessarily told to avoid any chance of it at all costs. One day, when best laid plans don't pan out, and you can't avoid it THEN what are you going to do? THAT'S when you need a plan, and easily memorable advice from experts/experienced individuals. Not when you are sitting on your couch deciding if you should ride/backpack/take the cross country tour or not.