New slide on Greylock?

While climbing up Greylock from Stony Ledge yesterday, I noticed a land slide on Greylock that I don't recall seeing in the past. Its on the west face, just to the north of the March Cataract Falls. Here's a picture I took;


I haven't been to Stony Ledge in a couple of years, and perhaps I didn't notice it because the foliage was out? I looked on Google Earth, and it doesn't show on that image (not sure of the date of that photo). It looks to be roughly 800 to 1000 feet long. If it's not of recent vintage, how long has it been there?

I noticed this slide while hiking the Hopper Trail yesterday. It is, as you say, about 800-1000 feet long. Best views (sorry, no pics) were from the Hopper Trail about 200' before you hit the campground area on Sperry Road. I had not noticed it before although I don't hike Greylock enough to use myself as a benchmark. It appears to be in the vicinity of March Cataract -- probably pretty easy to bushwhack over to it. Kind of a weird thing to see in MA... not many big slides.

-Dr. Wu

That's quite the slide. I wonder if that occurred during the heavy rains of May, 2006? I don't remember that slide when I hiked it in 2004.

grouseking

masshysteria said:

I looked on Google Earth, and it doesn't show on that image (not sure of the date of that photo). It looks to be roughly 800 to 1000 feet long. If it's not of recent vintage, how long has it been there?

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The Google Earth coverage for Greylock happens to be relatively old. The Digital Globe data (available in the Viewer) indicate that the image is older than 2002. (Greylock sits in a void for satellite coverage that makes one think there's a reason not to be publishing recent images. Are there "unusual" antennas or other structures present on the summit?)

Well, that might explain why the reconstruction of the Lodge has taken so long - obviously digging out a secret lair underneath it takes a while

dr_wu002 said:

I It appears to be in the vicinity of March Cataract -- probably pretty easy to bushwhack over to it. Kind of a weird thing to see in MA... not many big slides.

-Dr. Wu

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A subsequent recon hike in November does indeed bring the bottom of the slide very near the March cataract. It is only 150 feet to the north of the falls. There was too much ice on the slide to climb up it, however in the spring I will check out the top of the slide, via the Overlook Trail. By then, maybe the road will be open, and I can drive close to it!?

Some pics; http://good-times.webshots.com/album/568786061ImtvLR

masshysteria said:

A subsequent recon hike in November does indeed bring the bottom of the slide very near the March cataract. It is only 150 feet to the north of the falls. There was too much ice on the slide to climb up it, however in the spring I will check out the top of the slide, via the Overlook Trail. By then, maybe the road will be open, and I can drive close to it!?

Some pics; http://good-times.webshots.com/album/568786061ImtvLR

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Nice pictures. Slide looks doable.

Question: about how far up were you on the slide when you took that picture. If I'm not mistaken, March Cataract is fairly high up and it looks like the slide is about 1000' long.

-Dr. Wu

dr_wu002 said:

Nice pictures. Slide looks doable.

Question: about how far up were you on the slide when you took that picture. If I'm not mistaken, March Cataract is fairly high up and it looks like the slide is about 1000' long.

-Dr. Wu

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The pics were taken at the base of the slide, on top of a pile of rubble. One of the pictures shows the March Cataract looking through the woods from the base of the slide. It's only 150 feet away. The drainage from the slide joins the MC brook maybe 300 feet below the falls. The best closeup view of the slide ia actually from the trail that goes to the MC, about a 1/4 mile from the falls. You can see the lower half of the slide through the trees. And yes, I agree it is certainly climbable. I'm looking forward to scouting out the very top of it as soon as the snow clears.

masshysteria said:

The pics were taken at the base of the slide, on top of a pile of rubble. One of the pictures shows the March Cataract looking through the woods from the base of the slide. It's only 150 feet away. The drainage from the slide joins the MC brook maybe 300 feet below the falls. The best closeup view of the slide ia actually from the trail that goes to the MC, about a 1/4 mile from the falls. You can see the lower half of the slide through the trees. And yes, I agree it is certainly climbable. I'm looking forward to scouting out the very top of it as soon as the snow clears.

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I actually would like to 'whack over from the Hopper Trail. It's kind of a longer approach but every time I've walked the Hopper Trail, the woods are so open and pretty I always thought that I'd like to head in. Now I have an excuse. 'whack over from about 2000' -- definitely lose some elevation diving into the Hopper, cross the brook and push on to the slide. Probably have to slab along the ridge a little to hit it. Woods look so nice and tempting though -- I bet it's a fun 'whack. Climb the slide, top off and make way to summit and take Hopper Trail down. Sounds like a good trip sometime soon.

-Dr. Wu

When I first started up the Hopper Trail to recon the slide, my intention was to contour across the south end of the Hopper from the Hopper Trail, trying to maintain the same elevation. I hate losing altitude, only to have to regain it again! But after being able to see through the trees how close the March Cataract was to the slide, I opted to follow the HT up to the campground, and take the dead end trail to the MC. It was very windy and cold that day, so time was a factor.
You wouldn't have to cross the Hopper Brook, just follow it up to the base of the MC. The slide will be right there. If you get there before I can, please post something!

Boy, I'm going to go out on a limb here and say that you might have found a snow avalanche path, not a landslide. Your pictures of "rubble" don't seem to have the mud and rock entrained with the downed trees that I would have expected from a landslide. And the ground surface doesn't seem to have been scoured very deeply at all.

Do you have any other recollections or evidence to support or negate this hypothesis?

sardog1 said:

Boy, I'm going to go out on a limb here and say that you might have found a snow avalanche path, not a landslide. Your pictures of "rubble" don't seem to have the mud and rock entrained with the downed trees that I would have expected from a landslide. And the ground surface doesn't seem to have been scoured very deeply at all.

Do you have any other recollections or evidence to support or negate this hypothesis?

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Hmmm, that's interesting! I remember my first thought upon reaching the base was that there wasn't as much gravel in the ruble as I had expected. Having seen larger landslides in the ADK's, and their resulting gravel/tree/mud piles, this one did seem a little sparse.

Pic #8 is taken from the top of a pile of rubble near the bottom. It was a twisted contortion of trees and gravel. Now pic #7 was also taken from this mound, but looking downhill, where you can see a pile of trees, but no gravel. Pics #11 and #12 show debris piled against a tree, with some gravel, but not as much as you would expect.

Then again, pics #9 and #10 do show some scouring, but not complete gravel removal. Now I'm not sure?

Is there enough snowfall in the Berkshires to cause an avalanche forceful enough to uproot full grown hardwood trees? I have no knowledge of the mechanics of avalanches, so It's hard to draw a conclusion. But there is enough evidence to support your theory! Good catch!

Assuming a snow density of 20% (which is conservative for New England at times), a cubic meter (1,000,000 cubic centimeters or 1000 liters) of snow weighs 200 kg. A slide just ten meters wide that takes a half meter of snow depth with it and runs 50 meters then weighs: 200 kg x 10 x .5 x 50 = 50,000 kg, or 110,000 pounds. Yeah, it can do a job on trees in the way. And that's a relatively small avalanche.

One of the tipoffs for snow avalanche paths is a fairly uniform orientation of damaged vegetation parallel to the fall line, above the debris deposition zone. I think I can see some of that in one or more of your pictures.

A snow avalanche needs these things:

1. A suitable slope, typically 25 to 45 degrees, with the sweet spot at around 38.
2. An accumulation of snow on the slope.
3. A bond with the ground, or with an underlying snow layer, that is insufficient to hold the snow against the force of gravity.
4. "Something" to get things started, be it an unlucky skier, an unlucky mountain goat, or just that one last snowflake or a deterioration in the anchoring bond(s). Once it goes, it can propagate a rapidly shooting fracture of the snow crystal bonds that results in an avalanche.

In the words of Bruce Tremper, a well-known avalanche forecaster and author: "Gravity never sleeps."

I just went back and looked at pictures from Stony Ledge taken in April 2007 and can see it pretty clearly. This made me curious, so I did a quick search and turned up a shot from November '06:
http://www.penemco.com/matthew/hikes/Greylock_11_04_06/Greylock.html

Not as good, but the fourth one down here seems to show it in 2005:
http://outdoors.webshots.com/photo/1484284688072715070hHSwKq

But it seems to be missing from this one that was (presumably) taken in 2001:
http://www.mountainsummits.com/pictures/massachusetts/greylock/pages/greylock17.htm

So it would appear to have occurred sometime between '01 and '05.

Interesting pictures Taconic! Your pictures support the info that some members of the Haley family of Williamstown gave me; that it wasn't there in '01. They thought I was talking about the older slide that came down into the Hopper from around the Robinson Point area. They had no idea this slide was there!

Perhaps all questions will be answered upon the completion of an investigative expedition up the slide, with full photographic coverage. To be continued this spring, Same Bat time, same Bat channel........

sardog1 said:

Assuming a snow density of 20% (which is conservative for New England at times), a cubic meter (1,000,000 cubic centimeters or 1000 liters) of snow weighs 200 kg. A slide just ten meters wide that takes a half meter of snow depth with it and runs 50 meters then weighs: 200 kg x 10 x .5 x 50 = 50,000 kg, or 110,000 pounds. Yeah, it can do a job on trees in the way. And that's a relatively small avalanche.

One of the tipoffs for snow avalanche paths is a fairly uniform orientation of damaged vegetation parallel to the fall line, above the debris deposition zone. I think I can see some of that in one or more of your pictures.

Click to expand...

Can/does a snow avalanche take quantities of gravel with it? Assuming the graval is frozen?

masshysteria said:

Can/does a snow avalanche take quantities of gravel with it? Assuming the graval is frozen?

Click to expand...

Yes, but it's probably not going to happen most of the time. Most snow avalanches run on top of underlying snow. Big ones can scour things down right to the ground. Truly big ones can take mature Douglas firs and similar trees with them, but they're very rare -- that's how the trees can get big in a possible avalanche path.

I have tons of pictures from every corner of Greylock but wouldn't you know
when your looking for them

Here is a shot from Late Oct Nov 2000

Yipper, definitely not there in either pic from '01! A recon hike is scheduled for next week sometime , depending on weather. The Rockwell Road is not opening until around Memorial Day, so an easy approach from the road is negated. Perhaps a hike up the Hopper Trail, with a bushwack ala Dr. Wu's approach to the base. I may be different and come up from the Adams side, via Peck's Brook trail and come down the Hopper Trail to the March cataract Trail. In any event, there will be beaucoup pictures.
I may work over the DCR, and pick their collective brains about the date of the slide....... That is if there's anyone left there after the budget cuts!

Made the hike up the slide today, got sprinkled on a couple of times, otherwise, a good day to hike!

So here's the scoop; it starts at 2234 feet and tops out at 2755 feet, making it a 520 foot drop. The make up of the slide is loose gravel and rocks, reminding me of the Macomb west slide in the ADK's. However, this slide is a little steeper than Macomb. There is bedrock exposed in places, but the predominate loose gravel made choosing footholds very critical. It stays around 50 feet wide most of it's distance, but tapers near the head wall. There is a ledge at the bottom that requires a little thought to get around, as the gravel is saturated with water, making it even more slippery.

As far as the head wall at the top, there are 2 very large boulders perched next to it. Both are at least 30 feet long and 15 feet high. Upon reaching the top of these two boulders, it looks like they actually slid down the mountain about 10 feet, perhaps starting the slide. In the attached pictures, you can see where these boulders were attached to the ledge uphill from them, then broke free and slid about 10 feet. I think this may disprove the snow avalanche theory, Sardog.

From the head wall I continued up the steep woods and intersected the Overlook Trail, after only about a 10 minute walk. There was a crew of men clearing trees on the Overlook and upper Hopper Trails, and I thanked them for their efforts. They were from Mt. Wachusetts, where they had cleaned up the ice damage there. As far as ice damage, there was very little in the Hopper, until I got up to the Sperry campground. Then I noticed it more and more, especially on the trail to the March Cataract. I was told by the cutting crew that the worst damage seems to be from the south of the summit to the Visitors Center in Lanesboro.

Not one to take it easy, I noticed what looks to be a new slide northwest of the summit, while driving by Mt. Greylock High School. A gentleman I met on the Hopper Trail also thought he saw a new slide too. I took a compass bearing of it, and will have to mount an expedition to that one soon.

Pictures; http://community.webshots.com/album/571192914lzCpRO


As far as the date of this slide, I would have to say 2005. I found this site by Mark Rondeau where he has a picture of the slide from August, 2006. Judging by the 'cleaness' of the slide, it had to of been somewhere around that time. Also note he refers to it as the March Cataract, which is 150 feet to the south of where he took that picture.

http://markrondeau.com/greylocktwo.html