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KRobi
01-18-2011, 10:18 AM
I received this video from a friend. After sending it along to some others, one replied asking if I had seen it in NH rivers/stream? I have not but was wondering if any of you have seen something similar in NH? What river or stream and what time of year (late April, early May)?
Thanks,
Ken

YOSEMITE'S FRAZIL ICE
It is hard to imagine that Yosemite is only 60 miles from Fresno -- where it never ever snows and rarely gets below 32 F in the dead of winter.
This is an incredible video! It only happens in March and April. I have never seen a creek come to a complete stop like this before and start up again someplace else.
It's like a lava flow. There is a group of these videos, about Yosemite National Park. They are all very interesting, watch them all when you need something to do. Turn on your sound. Now just enjoy

http://www.youtube.com/watch_popup?v=9V9p4mFEYXc&vq=medium#t=15

nartreb
01-18-2011, 11:51 AM
Certainly see this on a very small scale in street drains, but I can't recall seeing it in streams. You need a major source of loose ice or snow that's easily swept into the water flow. I have seen something vaguely similar in glacial melt in Alaska, where small floes sometimes pile up and block a stream. Come to think of it, channels in Arctic (or Antarctic) sea ice can do much the same, except they can't overflow and change direction the way streams do. Very cool video.

Sheomet
01-29-2011, 11:49 PM
That's an awesome video, some really cool fluid dynamics going on there.

Daubie
01-30-2011, 01:27 PM
Frazil ice is actually a common phenomenum in the rivers and streams of New England, although usually not so dramatic as in the Yosemite video. The Army Corp of Engineers has a site with a lot of information on it, including some stories of flooding caused in large part by frazil ice, and amounting to millions in damages in some cases, many in New England. A relatively small scale incident occured in my hometown in north central Mass. not too long ago as documented in the link. A major contributor to the ice jam was frazil ice generated by an upstream dam and extremely cold temperatures. This site has more than you would ever want to know about ice jams and frazil ice.

http://www.crrel.usace.army.mil/icejams/trip_summaries03-04/Athol-22jan04.pdf

erugs
02-01-2011, 02:38 PM
Frazil ice is actually a common phenomenum in the rivers and streams of New England, although usually not so dramatic as in the Yosemite video.

I thought the process looked familiar to what I've seen here. I haven't ever actually seen the flow stop, then ease out and start elsewhere. That was a fascinating video.

Kurchian
02-01-2011, 09:43 PM
Captivating video!

I like the cold dessert references - "slurpy" and "snow cone".

Mike P.
02-02-2011, 02:15 PM
Nice video, also checked out some of the other Yosemite realted video's too. Kids enjoyed them too.

BF
02-02-2011, 05:40 PM
Very interesting. I've been there, but not during the months of March and April. Fascinating place. Thanks for sharing.

forestgnome
02-08-2011, 07:26 PM
awesome stuff...I've seen similar action here in NH but I can't remember where it was

Mike P.
02-09-2011, 05:40 PM
awesome stuff...I've seen similar action here in NH but I can't remember where it was

Would think it would have to be someplace wide & fairly flat, Bearcamp maybe

KRobi
02-09-2011, 06:24 PM
I've only seen it in "manmade" locations like Nartreb said, around drains or even when I've moved slush in the spring. Forestgnome, it would be great if you remember where as then I could let my friend know...which is how this got started. Nature is very cool!

islandside
03-22-2011, 11:26 AM
I found this rather unusual site on Mt Major the other day. It appears there had been an ice dam that caused the stream to overflow it's banks along the orange trail on Mt Major. The stream must have scooped out most of the leaves from last fall and deposited them in an alternate path beside the regular stream path. It looks like a pile of leaves but was a layer of leaves on top only and a mound of crunchy frozen stuff underneath.
Wish I had been there to witness it but it was probably pouring and not the best of hiking days!

arghman
03-25-2011, 08:20 PM
we get frazil ice frequently in winter on the Merrimack River in Manchester below the Amoskeag Dam. I've always assumed it's because of the turbulence.

Steve-o
03-25-2011, 09:17 PM
Very nice video. Better than anything I've seen on cable, in a long time...
I've seen similar but, never complete dams or re-routes.
Pretty intense !
I did, have the pleasure of showering under upper yosemite falls once.
Just a trickle though...

erugs
03-28-2011, 02:25 PM
we get frazil ice frequently in winter on the Merrimack River in Manchester below the Amoskeag Dam. I've always assumed it's because of the turbulence.

True. It is amazing how loud it is from my garage, which is right above the river. Once I'm tucked away inside my place, the sound proofing is good enough that I don't really hear it. (Or is it that my hearing is so bad that I don't hear the ice?) My first winter/spring there I was totally astonished by the commotion.