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Re: "Isolated Thunderstorms" means what?

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"Isolated Thunderstorms" means what?
May 28, 2009 04:58PM
Intellicast.com forecasts "isolated thunderstorms" for both of the days we are scheduled to be in the park. Intellicast does not provide a definition of what they mean by "isolated." What can we expect if that is the forecast for the day? Do thunderstorms mainly happen in the late afternoon, which is typical of deserts and other mountain ranges? Or can we expect a thunderstorm at any time of day? If the thunderstorms are "isolated," does that mean sunshine in between the storms, or will it be rainy all day long?
avatar Re: "Isolated Thunderstorms" means what?
May 28, 2009 05:39PM
They rain will be mostly in the afternoon and can be about 1X1 miles in size. (can be bigger) They can last 5 minutes or an hour. Can be just some rain or a torrent of hail with lots of lightening. Last weekend the thunderheads were pretty much well east of Yosemite Creek. It looked like Tuolumne Meadow was getting it. Yesterday and today the view from Modesto looked like the thunderheads were more numerous and more to the west than last weekend.



Old Dude
avatar Re: "Isolated Thunderstorms" means what?
May 28, 2009 06:28PM
You might want to think about this also. Lightning was severe along the Sierra crest this afternoon starting around 3:15. Flash flood warnings went up a couple times today near Reno. First was around Sierraville and then into Lassen County. The storms are quick and violent. Stay away from streams, creeks, and places that attract lightning, like high spots (aka Half Dome).
avatar Re: "Isolated Thunderstorms" means what?
May 28, 2009 06:56PM
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Vince
You might want to think about this also. Lightning was severe along the Sierra crest this afternoon starting around 3:15. Flash flood warnings went up a couple times today near Reno. First was around Sierraville and then into Lassen County. The storms are quick and violent. Stay away from streams, creeks, and places that attract lightning, like high spots (aka Half Dome).

Vince,

What's wrong being near streams and creeks? That's a new one on me. I know you don't want to be out on a lake where you stick right up from a flat surface but why would a stream or creek draw lightning?

Jim



Edited 2 time(s). Last edit at 05/28/2009 06:58PM by tomdisco.
avatar Re: "Isolated Thunderstorms" means what?
May 28, 2009 07:18PM
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tomdisco
Quote
Vince
You might want to think about this also. Lightning was severe along the Sierra crest this afternoon starting around 3:15. Flash flood warnings went up a couple times today near Reno. First was around Sierraville and then into Lassen County. The storms are quick and violent. Stay away from streams, creeks, and places that attract lightning, like high spots (aka Half Dome).

Vince,

What's wrong being near streams and creeks? That's a new one on me. I know you don't want to be out on a lake where you stick right up from a flat surface but why would a stream or creek draw lightning?

Jim

Ummmm...flash floods?
avatar Re: "Isolated Thunderstorms" means what?
May 29, 2009 10:01AM
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Vince
Quote
tomdisco
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Vince
You might want to think about this also. Lightning was severe along the Sierra crest this afternoon starting around 3:15. Flash flood warnings went up a couple times today near Reno. First was around Sierraville and then into Lassen County. The storms are quick and violent. Stay away from streams, creeks, and places that attract lightning, like high spots (aka Half Dome).

Vince,

What's wrong being near streams and creeks? That's a new one on me. I know you don't want to be out on a lake where you stick right up from a flat surface but why would a stream or creek draw lightning?

Jim

Ummmm...flash floods?

Sorry, Vince. I experienced another senior moment. Saw the word "lightning" and completely missed the words "flash floods".
As Dale would say, I'm getting dotty.

Jim
avatar Re: "Isolated Thunderstorms" means what?
May 29, 2009 11:00AM
Dale's words are "He's getting dotty." Usually glancing at me.



Old Dude
Re: "Isolated Thunderstorms" means what?
May 28, 2009 07:16PM
Thanks... we won't be going up Half Dome anyway because my Mom is 90 and in a wheelchair. But I was planning to watch the sunset from Glacier Point on Wednesday, is Glacier Point dangerous if a thunderstorm is in the area? And you're always safe just sitting in your car waiting out the storm, right? Actually I'm kind of looking forward to the drama and beauty of a good storm or two.
avatar Re: "Isolated Thunderstorms" means what?
May 28, 2009 07:21PM
Stay away from creeks and streams means don't be in one or right on the bank. Storms that drop a huge amount of water can cause a rapid swelling of the creek or stream sweeping you away to your death. How's that?



Old Dude
avatar Re: "Isolated Thunderstorms" means what?
May 28, 2009 07:31PM
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Bob Weaver
Thanks... we won't be going up Half Dome anyway because my Mom is 90 and in a wheelchair. But I was planning to watch the sunset from Glacier Point on Wednesday, is Glacier Point dangerous if a thunderstorm is in the area? And you're always safe just sitting in your car waiting out the storm, right? Actually I'm kind of looking forward to the drama and beauty of a good storm or two.

,http://www.nssl.noaa.gov/divisions/forecast/mag/ltg_guidelines.html>;

Safer locations during thunderstorms and locations to avoid

No place is absolutely safe from the lightning threat, however, some places are safer than others.
Large enclosed structures (substantially constructed buildings) tend to be much safer than smaller or open structures. The risk for lightning injury depends on whether the structure incorporates lightning protection, construction materials used, and the size of the structure (see NFPA 780, Appendix E & H).
In general, fully enclosed metal vehicles such as cars, trucks, buses, vans, fully enclosed farm vehicles, etc. with the windows rolled up provide good shelter from lightning. Avoid contact with metal or conducting surfaces outside or inside the vehicle.
AVOID being in or near high places and open fields, isolated trees, unprotected gazebos, rain or picnic shelters, baseball dugouts, communications towers, flagpoles, light poles, bleachers (metal or wood), metal fences, convertibles, golf carts, water (ocean, lakes, swimming pools, rivers, etc.).
When inside a building AVOID use of the telephone, taking a shower, washing your hands, doing dishes, or any contact with conductive surfaces with exposure to the outside such as metal door or window frames, electrical wiring, telephone wiring, cable TV wiring, plumbing, etc.
----



The cure for a fallacious argument is a better argument, not the suppression of ideas.
-- Carl Sagan
avatar Re: "Isolated Thunderstorms" means what?
May 28, 2009 07:39PM
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Frank Furter
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Bob Weaver
Thanks... we won't be going up Half Dome anyway because my Mom is 90 and in a wheelchair. But I was planning to watch the sunset from Glacier Point on Wednesday, is Glacier Point dangerous if a thunderstorm is in the area? And you're always safe just sitting in your car waiting out the storm, right? Actually I'm kind of looking forward to the drama and beauty of a good storm or two.

,http://www.nssl.noaa.gov/divisions/forecast/mag/ltg_guidelines.html>;

Safer locations during thunderstorms and locations to avoid


When inside a building AVOID use of the telephone, taking a shower, washing your hands, doing dishes, or any contact with conductive surfaces with exposure to the outside such as metal door or window frames, electrical wiring, telephone wiring, cable TV wiring, plumbing, etc.
----

I was weather spotting when living in Boulevard, CA, which tends to have violent T-storms. I was on the phone with the NWS reporting the severity and a spark leaped from the phone to my ear. I said, "better go now bye."
Re: "Isolated Thunderstorms" means what?
May 28, 2009 07:41PM
Here's a page with videos of Yosemite, and the 4th one down the page shows a thunderstorm at Tuolumne Meadows, although I didn't notice any lightning or hear any distinct thunder.

http://www.yosemitestock.com/category/yosemite-videos/yosemite-videos-2009
Re: "Isolated Thunderstorms" means what?
May 28, 2009 08:40PM
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Bob Weaver
Thanks... we won't be going up Half Dome anyway because my Mom is 90 and in a wheelchair. But I was planning to watch the sunset from Glacier Point on Wednesday, is Glacier Point dangerous if a thunderstorm is in the area? And you're always safe just sitting in your car waiting out the storm, right? Actually I'm kind of looking forward to the drama and beauty of a good storm or two.

The view is really dramatic from Glacier Point during a thunderstorm, or even with the clouds. A couple of years ago we watched the lightning hitting peaks near Tioga Rd. and also the Clark Range from Glacier (and watched the people on Half Dome, which fortunately didn't get hit). It didn't seem particularly unsafe at Glacier, but I suppose if the storm is right on you, anywhere seems unsafe 8^).

I was in the valley the 18th when a hard-hitting thunderstorm came along. It had been warm and sunny all morning, and at about 1:30 PM there were a few clouds, and I was thinking maybe we wouldn't have had to cancel the Half Dome hike, had we known. By about 2:30 it looked like this from above tunnel view:


An hour later, I had gone down to the Lodge to get a cup of coffee, and as I left, it had begun raining hard and there was a line of cars as far as I could see, leaving via Northside drive. As I made my way back to the campground to check the tent, I began to wonder if there could have been some flash flood evacuation warning; being May, and hot weather, and hard rain, it's the correct formula. But I guess it was just the day visitors bailing out.

It literally poured, thundered and lightning constantly (~5 seconds apart) for about an hour, then quit, and by 6 or so it was bright and sunny again. So that was sort of an 'isolated shower', I guess. It was a bit spooky, and with it that close, may have been uncomfortable at Glacier.

Here's an infrared photo (which always brings out the clouds well) I took about the same time as the above one, not long before the rain:


Neither of the photos are from Glacier Point, but the view there is more dramatic, if anything.



Gary
Yosemite Photo Galleries: http://www.pbase.com/roberthouse/yo
Re: "Isolated Thunderstorms" means what?
May 28, 2009 09:18PM
Thanks very much for all that information and the photos. That infrared photo is beautiful. It makes it look as if everything is covered with snow and ice.
avatar Re: "Isolated Thunderstorms" means what?
May 28, 2009 07:30PM
Had a pretty good one at Minaret Falls campground a few years ago and literally watched the (middle fork) San Joaquin River rise six inches in 15 minutes.
avatar Re: "Isolated Thunderstorms" means what?
May 28, 2009 08:05PM
I'm out of gas money till June 5 so this weekend I'm stuck for stuff within what I can see nearby. Which in Reno/Sparks means lots of potential energy. I won't go to Tahoe, it's always a mess. Should find something for an entertaining video around Stampede if the weather cooperates. Images of me with skeleton showing should be amusing.
avatar Re: "Isolated Thunderstorms" means what?
May 29, 2009 10:21AM
O.K., say you are a day and a half into the wilderness at 9,000' on the Lewis Creek trail to Vogelsang Pass at 3:00 PM when a major thunderstorm hits. There are 1,000' + peaks all around you. You have to do something. The best suggestion I've read is to find soil to stand on (not bare rock) in a semi-open area away from tall trees in a squatting position. One source even said it's O.K. to stand or crouch within a bunch of smaller trees, just not directly under any particular one. How many of you more experienced hikers agree with any of this? If not, what do you recommend? This is serious stuff we all need to know.

Jim
avatar Re: "Isolated Thunderstorms" means what?
May 29, 2009 11:06AM
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tomdisco
O.K., say you are a day and a half into the wilderness at 9,000' on the Lewis Creek trail to Vogelsang Pass at 3:00 PM when a major thunderstorm hits. There are 1,000' + peaks all around you. You have to do something. The best suggestion I've read is to find soil to stand on (not bare rock) in a semi-open area away from tall trees in a squatting position. One source even said it's O.K. to stand or crouch within a bunch of smaller trees, just not directly under any particular one. How many of you more experienced hikers agree with any of this? If not, what do you recommend? This is serious stuff we all need to know.

Jim

I posted a whole bunch of references from NOAA on another thread <http://yosemitenews.info/forum/read.php?1,12015,12015#msg-12015>; that may answer some of your questions.
The underlying tone of the recommendations is not what is "safe" to do in the wild as the experts indicate that lightning safe shelter is preferred in all circumstances. There are some continginency options offered. Apparently the lightning does not "choose" a spot until the final 30 meters or so. Couching and "Insulating" from the ground seems reasonable, but I do not find any proof offered that supports those manuevers. My preference, personally, if my hair is bristling and skin tingling would be to find the lowest area reasonably accessible without standing in a pool of water or crouching under rocks some distance from the largest tree (hopefully more than 100 ft tall) in the area. I would sit on my backpack, and wait it out-- 30/30 rule.



The cure for a fallacious argument is a better argument, not the suppression of ideas.
-- Carl Sagan
avatar Re: "Isolated Thunderstorms" means what?
May 31, 2009 09:30AM
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tomdisco
One source even said it's O.K. to stand or crouch within a bunch of smaller trees, just not directly under any particular one. How many of you more experienced hikers agree with any of this? If not, what do you recommend?
Jim
Jim, In the Sierra what I do is keep looking around at the trees. Are they pointy? Or have a bunch been wacked by lightning already?
If the later is true... Head lower... If the former, then I'd just head into the stand o trees and wait it out.
I've never had my hair standing on end or had "sparks" coming from my shoes so you can take this as you wish.
There was some thunder this weekend where I was. I didn't see any lightning.

The wife liked this one (she usually hates my pictures) :
(I tell her I am documenting my trip for myself so I can relive my gory)

avatar Re: "Isolated Thunderstorms" means what?
May 31, 2009 10:07AM
Lookie all the snow!! What elevation are you at (8,500+?) Of course, it begs the question:

Where are you??Bee Cowboy
avatar Re: "Isolated Thunderstorms" means what?
May 30, 2009 07:31PM
avatar Re: "Isolated Thunderstorms" means what?
May 31, 2009 09:32PM
I'll give you a hint:

Goat Stop
avatar Re: "Isolated Thunderstorms" means what?
May 31, 2009 09:34PM
O.. btw.. eeek... love the Lembert Dome pict.
Got one of Tenaya? Any ice still a floating in there?
avatar Re: "Isolated Thunderstorms" means what?
June 01, 2009 12:26AM
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bill-e-g
O.. btw.. eeek... love the Lembert Dome pict.
Got one of Tenaya? Any ice still a floating in there?

No ice:

http://yosemitephotos.net/main.php/v/yosemite/sh-dscn3184.jpg.html
avatar Re: "Isolated Thunderstorms" means what?
June 01, 2009 06:12PM
No ice. This is terrific. I can't wait. If I start walking right now I'll be there by mid-July.

Jim
Re: "Isolated Thunderstorms" means what?
June 05, 2009 11:23PM
Thunderstorms were predicted for both days we were there but we never saw or heard one. On Wednesday it was cloudy and overcast most of the day but the sun came out partially at the end of the day. There was only one brief rain, in the early afternoon but it lasted only 10 minutes or so. June 4 alternated between clouds and brilliant sunshine, though still cold at the higher elevations, but no storms that I could see or hear.
Re: "Isolated Thunderstorms" means what?
June 07, 2009 12:20PM
Got chased off of Mt Whitney last weekend at Trail Crest by an "isolated thunderstorm" though I swear it must've had friends, because at 13,600 ft. it was, what's the word, Biblical? One moment we heard the distant rumble of thunder, and before I could put even one crampon back on, all hell broke loose. Couldn't get down fast enough though, because due to the previous several days of "isolated" thunderstorms, many of the switchbacks were nothing but bottomless snowfields that we had to navigate with crampons and ice axes (mini lightning rods, just as our hiking poles which were unsfafely stowed in our daypacks). At sea-level you're essentially beneath the thunderclouds. Much different when you're right in them. My first, and hopefully last time. One guy I saw later who got stuck on the crest not far from the summit curled up into a little ball beneath some granite boulders (where else ya gonna go). He said the strikes were within 30 ft. Scary, scary, scary. The next day down at the Whitney Portal Store over a big buger and beer looking up at the daily gathering storm clouds, some guy going up to Trail Camp actually said the odds of getting hit by lightning was less than getting hit by a car. Where do they get this stuff? There's no cars on Whitney, is there?

Should've figured as much. Driving through Yosemite to 395 last Friday, a good portion of the road was covered in hail, and way too many rented RVs.
Re: "Isolated Thunderstorms" means what?
June 07, 2009 05:28PM
Yes, I've heard Whitney summit is pretty inaccessible right now, despite how it was recently.

Beware of lightning advice from strangers though. Remember, if you've read the book "Shattered Air", those guys that went up Half Dome were sure of themselves and no doubt would have liked the "hit by a car advice".

I've heard these 'advisors' as we left the HD cables retreating from incoming storm clouds, advising people for example that they wouldn't advise anyone to go up, but they were going ahead because they were experienced.

That advice is probably right though. If there's no lightning, there's little chance of getting hit by it, same with cars. Going up to a summit in a lightning storm? Still maybe no more chance of getting hit than you would getting hit by a car. While crossing the LA freeway on a rainy night in rush hour traffic 8^).



Gary
Yosemite Photo Galleries: http://www.pbase.com/roberthouse/yo
avatar Re: "Isolated Thunderstorms" means what?
June 07, 2009 05:41PM
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Sierrafan
If there's no lightning, there's little chance of getting hit by it, same with cars.
Unless it is a positive lightning "bolt out of the blue" event (see lightning thread).



The cure for a fallacious argument is a better argument, not the suppression of ideas.
-- Carl Sagan
avatar Re: "Isolated Thunderstorms" means what?
June 07, 2009 06:06PM
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Frank Furter
Unless it is a positive lightning "bolt out of the blue" event (see lightning thread).

What about ball lightning? Grinning Devil
Re: "Isolated Thunderstorms" means what?
June 07, 2009 10:34PM
On Friday, we were at the Alabama Hills and there were 2 guys taking pictures of themselves on the rocks. Before they left, they asked me if I would take a picture of them in their truck on the way up Whitney Portal road. I took the picture of them sitting in their truck, and it would be one of a series of documentary pictures of their trip. They were both around 25 years old I would estimate. They were planning to start hiking toward the summit of Whitney at about 4 a.m. on Saturday morning. And they would be back down to their camp before nightfall. I asked them what the temperature would be at the summit and they said it was predicted to be 19 F. I wished them a good trip and waved as they drove away. I wonder if they ever made the climb.
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