Treebeard's Stumper Answer 6 November 98

East-West Mountains

The Santa Ynez Mountains that we see from Dunn Middle School are part of the Transverse Ranges, one of the few mountain systems in North America that run east-west rather than north-south. (See map.) It takes local residents years to learn that they're really looking south across the ocean towards the Channel Islands. What is the next land you would come to if you kept going past the islands? What other mountain ranges run east-west? Does this unusual local geography have any important effect on the natural plant and animal life in the Santa Ynez Mountains?

Look out to sea from the crest of the east-west Santa Ynez Mountains. The next landmass is Antarctica, not Hawaii! The Brooks Range in Alaska, the Uintas in Utah, and the Holyoke Range in Massachusetts also run east-west, but there are few others in North America. One effect of this unusual orientation is that one side of our mountains always points towards the sun, and the other points away. The cool north slopes shelter giant banana slugs and surprising native plants like wild huckleberries that really belong much further north.

Note: Looking for east-west ranges in an atlas is a fun scavenger hunt! Let me know of any we've missed. Here's our list so far:

• The Transverse Ranges in Southern California include the Santa Ynez Mountains (of course), the San Gabriel Mountains, and the San Bernardino Mountains. These ranges continue east into the desert, but they become less distinct, and break into a number of smaller ranges, including the Pinto Mountains and the Chocolate Mountains.

• The Uinta Mountains are a long east-west range in northern Utah near the notch. Several years ago, my family drove the highway between Dinosaur National Monument and Flaming Gorge Reservoir in Wyoming, skirting the edge of the Uinta Wilderness. I want to go back!

• The Brooks Range in northern Alaska is flanked by several other east-west ranges, including the DeLong Mountains, the Endicott Mountains, and the Philip Smith Mountains.

• The Alaska Range turns east-west for a ways east of Denali (Mt. McKinley). The Wrangell Mountains and the Chugach Mountains are nearby.

• The Mogollon Rim runs east-west across northern Arizona into New Mexico, though I'm not sure that counts as a mountain range. The Balcones Escarpment along the south edge of the Edwards Plateau in west Texas also runs east-west.

• The Ouachita and the Boston Mountains in Arkansas on the edge of the Ozark Plateau run east-west.

• I found the Holyoke Range in Massachusetts by doing a web search on "east-west mountain". There is a report from the New England Botanical Club about these interesting East Coast mountains.

• There are hills running across the state of Coahuila in northern Mexico between Torreón and Monterrey. I don't know their name, but they run east-west between the Sierra Madre ranges.

• The Sierra Madre del Sur in southern Mexico and the Sierra Madre in Central America include a number of distinct east-west ranges with beautiful names like the Serranis Huapi, the Altos Cuchumatanes, and the Cordillera Dariene.

• The Caribbean Islands of Cuba, Jamaica, Hispaniola, and Puerto Rico are formed by east-west mountains.

• The Hawaiian Islands are a nearly east-west chain of volcanic peaks. Think of them as an almost submerged mountain range.

• There are several east-west ranges in South America, though none stand out in an atlas like the Andes. The Coast Range of Venezuela is at the extreme north of South America. The Amazon Basin is bordered by the Sierra Pacaraima and the Tumuc-Humac Mountains (great name!) on the north and the Serra dos Parecis along the edge of the Mato Grosso Plateau to the south.

• East-west mountains seem to be the norm across North Africa and Eurasia, including the Atlas Mountains, the Pyrenees, the Alps, the Himalayas, and many more.

Learning the lay of the land is Geography. Learning why it lays that way is Geomorphology.

As I understand it, the east-west mountains across Eurasia are being formed by tectonic forces as Africa and India drift north and collide into Europe and Asia. But our North American Plate is traveling west, so most of our mountains run north-south, formed as the "crumpled bumper" of our collision with the Pacific Plate. Our east-west mountains are the exceptions, and have interesting geological causes!

My "Uncle Bernie" was Harvard geologist and paleontologist Bernhard Kummel, who never quite bought the new "continental drift" theories before he died. When I was a kid, I received a 200 pound box of fossils one year for Christmas. In 3rd grade, I wanted to be a "paleontologist," which confused my teachers who didn't know what it meant! I still have shelves of local fossils that I've collected in my personal museum downstairs. I think I've grown into Uncle Bernie's old-school sense that geology should come from a rock in the hand, not a computer model on someone's desk. I don't trust these grand theories, but they sure explain a lot in a few words!

The east-west Santa Ynez Mountains where I live form a natural barrier between Southern and Central Califfornia. Many native plant species find their northernmost and southernmost extension here, which makes the natural history of these mountains partucularly interesting. Graybear (from Virginia) writes:

My guess is that the climate there is much warmer and more Mediterranean than the northern side of the mountains. The range probably protects you from the northern winds, and reduces the amount of cold precipitation since the clouds will often drop their water as they climb over the mountain. The south facing mountains act as a passive solar collector, retaining heat enabling a greenhouse effect.

I remember reading (*somewhere*) that the south-facing slopes of the Santa Ynez Mountains (after a fire) have one of the highest plant growth rates ever measured in terms of total biomass accumulation over time. Our storms usually come from the north, but they pull in moisture from the south. (See my stumper The Rain and the Wind.) As moist air is drawn over the east-west mountains, it dumps more than its share of rain because of orographic lifting. At my home on San Marcos Pass, we regularly measure twice the rainfall that Santa Barbara gets on the coast just a few miles away. While searching the Web, I found two technical papers from NOAA (here and here) comparing different computer weather models and complaining that they typically underestimate the Transverse Range rainfall by a large amount. I believe it.

Another influence might be fog. The Santa Ynez Mountains form a continuous south-facing mountain wall along the Pacific coast from Point Arguello nearly 70 miles east to Ojai. The Santa Ynez Valley behind the mountains is only about 10 miles from the ocean along its entire length. This promotes the inland flow of fog and onshore ocean breezes which definitely effect local plant communities.

Graybear also writes:

The interesting thing about this stumper, to me anyway, is the relative positions of the continents. The various projections of the spherical earth on a flat plane give us a distorted view of geography. We think of South America being due south of North America, but I live on the east coast (generally) and I am due north only of the western tip of Ecuador and Peru. A couple of degrees farther west, and I would have missed South America also. I was also surprised that I missed Florida, on the other hand, Virginia extends farther west than Detroit, Michigan.

I don't think of Santa Barbara as being due south of Lake Tahoe or north of Pitcairn Island. It's good to have a globe as well as an atlas!

Graybear also sent two brain-teasers:

• If you are travelling through the Panama Canal from east to west, which ocean will you get to?

• Recently this telephone conversation took place in the continental U.S.:

  A: "What time is it where you live?"
  B: "1:30"
  A: "That's what time it is here, also, but I'm in a west coast state and you are in an east coast state!"
  B: "How can that be?????"
  

My atlas helped with the first. I'm still thinking about the second...

There's more discussion of local natural history stumpers at Treebeard's Flora, part of the Santa Barbara Outdoors site.

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