Nearly Identical Elevation, But Very Different Summits: North Twin vs. Eisenhower

[1HappyHiker]

I have an oddball question (which won’t surprise some folks!) And, if the question has already been “asked & answered” on this forum, then please just “link me to it”. I searched, but maybe not diligently enough!

My question is this. What causes the summit of Eisenhower to be more “alpine-ish” and rugged than the summit of North Twin?
According to the AMC maps, North Twin has an elevation of 4,761 ft which is nearly identical to Eisenhower at 4,760 ft.

I suspect the answer might be related to a term that’s often used in the real estate profession, i.e. “location, location, location”.
Perhaps Eisenhower’s location relative to Mt. Washington causes it to be more exposed to wind erosion than North Twin??

 

[Frodo]

I think it has more to do with "valley, valley, valley". Eisenhower is part of the exposed Presidential Range (which has a huge valley in front to give it the brunt of the winds).

The Twins are more protected by having the Franconia's blocking much of the wind...

 

[cushetunk]

I think this is one specific case of a very interesting question: why is this natural place the way it is? And while I don't know the answer for these two peaks, there are a number of things I would look at and hypothesize about.

1) Wind: yes, Mount Washington gets more wind and maybe some of that gets deflected down towards Ike. But for wind I think the terrain to the NW of each peak would also influence the general wind patterns. Anyway I don't think wind is necessarily the deciding factor for treeline.

2) Cloud cover: I wonder if Mount Washington creates more clouds, and so puts Ike into the fog more. Freezing fog and rime I think would have a pretty dramatic effect on trees, so this may be a greater factor in treeline than just wind speed.

3) Geology: Different rock types with different potential for creating soil, and pockets for tree roots, weathering rates to make nutrients available. Even if they are both granites there could be some striking differences.

4) Disturbance history: Maybe 1000 years ago the summit of Ike did have trees, but then lightening started a fire which burned all the trees, and the harsh weather prevented them from ever growing back.

 

[Mattl]

I think it is mostly based on topography, Eisenhower is part of the long Presidential Range that runs north to south from the huge Ammon-Bretton valley. Like someone said, Franconia Ridge has a sig impact on S Twin. Eisenhower gets extreme wind because of this and not allowing any boreal forest past a certain point. Valleys like that allow wind to ride up without any blocking from other mountains. I don't think fires had a large impact on Eisenhower, I know S Twin was near plenty of them though. -Mattl

 

[Waumbek]

I suspect the answer might be related to a term that’s often used in the real estate profession, i.e. “location, location, location”.

Whatver causes it--topography, location, etc.--it's "wind, wind, wind" that affects Eisenhower. Whenever I top out in the col between Franklin and Ike, I always brace for the wind tunnel effect there.

 

[NewHampshire]

Whatver causes it--topography, location, etc.--it's "wind, wind, wind" that affects Eisenhower. Whenever I top out in the col between Franklin and Ike, I always brace for the wind tunnel effect there.

I have to agree and offer up yet another great example....Moosilauke. It is, as far as this discussion is concerned, barely any taller than the other two, yet with no major massif to block wind we have a considerably large alpine zone also on Moosilauke......

Brian

 

[bikehikeskifish]

Both Ike and Moosilauke are domes - does that mean anything? Ike used to be, after all, Pleasant Dome.

Tim

 

[Kevin Judy and Emma]

My 2 cents

I believe in the wind theories, but I would not dismiss fire being the culprit, either.

I have read that Chocorua was a treed summit until fire burned the vegetation and rain and wind eroded the soil leaving bare rock. I suspect Eisenhower suffered the same fate, but I cannot offer any proof. Maybe someone else can.

KDT

 

[NewHampshire]

I believe in the wind theories, but I would not dismiss fire being the culprit, either.

I have read that Chocorua was a treed summit until fire burned the vegetation and rain and wind eroded the soil leaving bare rock. I suspect Eisenhower suffered the same fate, but I cannot offer any proof. Maybe someone else can.

KDT

I would have to double check in my copy, but I think Forest and Crag made occasional reference that Ike was always bald, or at least as long as recorded human ascents are concerned. I think, however, it was always as barren as it's taller kin to the north.

Brian

 

[cushetunk]

The Presidential Range is located at the convergence of weather derived from three different air masses, which give rise to frequent cloud events and strong winds. For the Presidential Range, the frequency of clouds by elevation commonly approximates the treeline boundary. The summit of Mount Washington is in the clouds over 55% of the time. During the winter, rime ice deposition, caused by enshrouding clouds propelled by strong winds, can give rise to heavy mechanical loading and subsequent damage to the vegetation. Blowing snow on the mountains has considerable abrasive action before it is blown off the more exposed alpine zone and deposited in the ravines and snowfields. Bliss (1963) attributed the distribution of nine plant community types on Mount Washington to two gradients: 1) an increasing snow depth and late spring melt gradient, and 2) increasing summer atmospheric and soil moisture and fog. Bliss suggested that these moisture gradients are strongly influenced by topographic features of aspect and elevation.

(...)

Biologists and climatologists have recognized that the limit of tree growth in both the alpine zone and the arctic in North America and Eurasia, north of the tropics, approximates the 10 °C isotherm for the warmest month of the year, usually July (Arno and Hammerly 1984). Temperature declines approximately 1-2 °C for every 300 m in elevation gain, due to the reduction in atmospheric pressure and expansion of the air. The wide elevation ranges we measured in the ATE and uppermost krummholz islands for both mountain ranges suggest that the concept of treeline and the upper limits of tree growth as a temperature-caused phenomena on the Northeast’s highest peaks is far too simplistic. We hypothesize that tree growth on the northeastern US mountains is strongly influenced by the climatic growing season and exposure factors. Although elevation is recognized as an important factor in determining the location of krummholz, models that incorporate topographic exposure with elevation more accurately predict treeline for the Presidential Range (Bryant and others 1991). The extent of treeline on the Presidential and Katahdin Range reaches higher elevations in the valleys compared to the ridges. This corresponds to the exposure factors of wind and rime ice formation in the winter.

http://www.fs.fed.us/rm/pubs/rmrs_p015_3/rmrs_p015_3_093_101.pdf

scholar.google.com does wonders.

 

[1HappyHiker]

http://www.fs.fed.us/rm/pubs/rmrs_p015_3/rmrs_p015_3_093_101.pdf

scholar.google.com does wonders.

Thanks Cushetunk for the excellent information you quoted from the article authored by Kimball & Weihrauch that was presented in the USDA Forest Service Proceedings. That information thoroughly answers the question I posted!!

Also, thanks for the link to scholor.google.com. I was unaware of that Google had set up that search engine subset.

 

[Mike P.]

What I found interesting as far as summits that change from summer to winter. On my recent North Twin trail, I found the addition of 4-6 feet of snow on North Twin changed the summit a lot.

In fact, IMO, North Twin may change more than any other summit I've been on from it's summer conditions to it's winter conditions just by adding some snow. (well 4+ feet may be more than some)

Pierce, Garfield & Liberty in summer or winter remain wooded trips except for the last little bit which offer great views. (more open time on Pierce) You need a lot of snow on South Carter (like last Feb) in order to get a view from over the trees. Ike, Moose, Bondcliff, the Northern Presidentials are bald places where the wind can sweep across mercilessly & the views can be spectacular anytime of year. Route finding when Cairns are snow & ice cvered is an issue. You might need 20 feet of snow to get a view from Zealand's summit

NT in summer provides a good view from the ledges just before the summit (on the NT trail) & also the ledge just down the spur from the summit but otherwise between the ledge & the summit, it's mostly a walk in tall scrub which most of the time prevents views. With a few feet of snow though, most of the trip between the NT trail ledge & the summit was only in 3-5 feet scrub, better views, much more exposure (Mike & I did not even take tha last few steps on the spur ledge path because we could see enough from 2/3's of the way over the trees.)

So I've learned a new respects & admiration for North Twin

 

[Kevin Judy and Emma]

Excellent

Excellent explanation about treeline in the Presi's. Thanks for pointing us to that!

KDT

 

[bikehikeskifish]

In Not Without Peril, p. 145, Nicholas Howe writes


The Crawford Path is one the most delightful outings in the White Mountains and the terrain is easy. The Northern Peaks we sharply cut by the glaciers and they're jagged pyramids above the main ridge.. The ice sheet slid over the first five of the Southern Peaks, so they have rounded summits joined by moderate depressions in the ridge; only Monroe has a jagged outline.


Tim