Adirondack Slides

June 10, 2013

This managing editor has known the Adirondack Mountains from a distance as great panoramic scenery viewed from the Vermont side of Lake Champlain for most of his life.  He admired the wonderful scenery as a child.  That was only on occasion, since in those years he lived on the eastern side of Vermont and the big mountains viewed from there were the Whites of New Hampshire.  But almost every day as a college student at the University of Vermont and working summers on his parents’ dairy farm in the Champlain Valley, the magnificent range that rises over 5,000 feet out of the lake were available eye candy daily (allowing for weather and visibility).


Follow up:

It wasn’t until age 62 that my first excursion was taken into the “Dacks”, as insiders know them.  It was love at first sight and for the next seven years numerous excursions into the “North Country” wonderland ensued.  License plates were even converted to the vanity logo “CATSNDAX” to the envy of thousands of outdoor enthusiasts who hadn’t thought of doing that themselves.  (The CATS of course refer to the other high peak region of New York, the Catskills, which rise spectacularly 4,000 from the west bank of the Hudson.)

A Little Geology

The Adirondacks are the youngest mountains in the eastern half of the United States.  They are actually the southern end of the Laurentian mountain range of Quebec and the southern most extension of the Canadian Shield, which has been growing as an upthrust dome for up to 20 million years.  The most recent part of this dome is the Adirondacks which is estimated to be only about 5 million years old.

The rocks thrust up by the Canadian shield dome are from deep within the earth’s crust, with ages up to 1 billion years.  The dome under the Adirondacks is still rising, with an estimated elevation gain of 1-3 mm per year, net of erosion losses.  If this were to continue for another 5 million years at the average rate of 1.5 mm per year, the Adirondacks would surpass the current peaks of the Himalayan Mountains, reaching around 30,000 feet.   Of course, the strong plate tectonics between the Indian and Asiatic plates are driving the Himalayas skyward at an even faster rate, about 5 mm a year.  The Adirondacks can never win such a race, even if all forces continued acting for millions of years.

The other high mountains of the eastern U.S., the Appalachians, which extend from Newfoundland to Alabama, to the east and south of the Canadian Shield, are almost 100 times as old as the Adirondacks.  They were formed by tectonic plate collisions nearly 500 million years ago.

A Little Recreation

An article in The Adirondack Almanack by Kevin “Mudrat” MacKenzie brought your editor ‘s mind back to his “Shangri-La”.  The article describes the ascent of a slide on Giant Mountain, the 12th highest peak in the Adirondacks. (The peak is also known as Giant of the Valley – when viewed from the east – for its impressive rise to 4,627 feet at a lesser distance from Lake Champlain than all but one other High Peak.)

There are 46 peaks in the Adirondacks that are listed as required climbs to join a club known as the Adirondack 46ers.  The nominal elevation to make the list is 4,000 feet, although four have been determined to be just short of the designated elevation.  And a peak that is not on the list is now known to exceed 4,000 feet.

The Adirondacks, because of their youth, have features that are found much less frequently on other eastern U.S. mountains:  Slides.  There is much less surface soil over the crystalline metamorphic rocks of the Adirondacks compared to the other much older mountains of the East.  When there are periods of very heavy rainfall these thin soils are loosened and flow down the steeper slopes creating open slides, composed mostly of exposed rock with some areas of remaining dirt and gravel.  Slides on steep slopes elsewhere in the eastern U.S. do occur, but not with the density found in the Adirondacks.

In the picture below, there are slides visible on the north face of Mount Marcy, the highest peak in New York.  The surface of these slides is similar to the elevations above 4,700 feet or so on the highest peaks, which have only small areas of thin soils and much exposed rock.


North face of Mount Marcy in winter, summit 5,344 feet.

The slide that Mudcat, accompanied by Adirondack Explorer editor Phil Brown, described in The Adirondack Almanack is shown in the mosaic below.


If there is any problem viewing the composite here, try The Adirondack Almanack.

Note: The caption photo at the beginning of the article might appear to be quite a way up the mountain.  The composite shows it was taken at the beginning of the climb.

A number of peaks have multiple slides, as does the west face of Giant, seen in the picture below.  The Bottle Slide is the long slide on the left, leading up to the 80 foot cliff below the summit.  The article at The Adirondack Almanack explains how hikers can avoid trying to scale the cliffs, which would require technical equipment.


Another spectacular collection of slides is found on Mount Colden (4,714 feet), shown below (from Adirondack Hikes:  An Upstate NY Hiking Diary), where the west face drops straight into Avalanche Lake.

Mount Colden, viewed from the 5,114 foot Alogonquin.  Mt. Marcy center background.adirondacks-slides-colden-from-algonquin

In the above picture, Giant is the broad topped peak on the horizon, left.  Also, lower left is a slide created in the early 2000s which dumped a 20 foot high pile of debris into Avalanche Pass, blocking the trail and requiring a complete relocation.  The picture below shows the debris blocking the old trail.


All Sizes and Shapes

Slides can be very narrow compared to their length, as is the Bennies Brook Slide on Lower Wolfjaw.  This slide is over a mile long and averages 50-70 yards (+/-) in width.


The slides’ landscape is constantly changing with new slides created with every major storm.  The above picture, by famous Adirdondack photographer Carl Heilman II, is from “New Adirondack Slide Guide” published by Adirondack Explorer after Hurricane Irene poured copious rainfall onto the Adirondacks in 2011.  Many new slides were created and Bennies Brook was slightly widened (upper portion) and extended much further down the mountain.  The lengthy new slide area is the debris covered slash at the bottom of the picture.  As narrow as the slide appears, the photo below gives perspective, taken pre-Irene in 2003 (from Adirondack High Peaks).


The trees visible at the bottom of the slide in 2003 now are split by a continuation of the slide much further down the mountain.

An example of a wide slide is visible on the horizon (center) in the above picture.   The slide on Big Slide Mountain, about 2 1/2 miles distant from the camera, is over 1/4 mile wide and 1/4 mile down the side of the mountain, with a slope of 35 degrees and up, exceeding 45 degrees in places.


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