Schooled In Nature
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SCHOOLED IN NATURE
The Fresno Bee
26 February 2008
No less an authority than Henry David Thoreau compared the sensation of tramping through snow to walking in a cloudy sky upside down.
A beautiful description, but there’s a catch: You’d better be wearing snowshoes.
Without snowshoes, walking through snow isn’t nearly as enjoyable — or poetic — as ranger Dick Ewart points out Saturday morning before leading a 5-hour snowshoe hike sponsored by the Yosemite Association.
“Indians figured out 10,000 years ago that you’ll sink deep in the snow unless you make your feet real wide,” Ewart tells the group.
A 32-year Yosemite veteran, Ewart is as much a fixture at Badger Pass as the historic main lodge. During the decades, he’s introduced thousands of park visitors to the secret splendor of winter while teaching them about the natural world.
After introducing the history of snowshoeing and displaying several different types of snowshoes, Ewart leads uphill from the base area and off the groomed ski slope. Since it had snowed more than a foot overnight, the going gets tougher as we sink with every step.
“People pay a lot of money to use stair-step machines,” he says. “You get it up here for free.”
Before long, we come across animal tracks that are partially covered by snow. The tracks are so faint it’s impossible to tell what direction the animal is traveling, though Ewart believes it’s probably a long-tailed weasel.
Someone asks Ewart why there are only two sets of tracks instead of four, which is what you’d expect a four-legged critter would leave behind.
“For the same reason that everybody is following my path,” Ewart says. “It’s a lot easier to get around.”
He goes on to explain that some animals change their gait in the winter so that their hind feet land in the same hole as their front feet, leaving only one print. It’s called direct registering.
Threatening skies loom overhead as we arrive at the top of the ski slope. Mount Hoffman, which lies 10 miles to the north, is almost completely enveloped in storm clouds.
Even so, Ewart continues to impart knowledge.
We learn that winter is caused by the earth’s 23-degree tilt away from the sun, which in turn makes the sun’s rays hit the earth at a lower angle. Because of the glancing nature of these rays, less energy is transferred to the earth’s surface in the form of heat.
We learn that air, like any gas, expands and cools at higher elevations. Expanding on this concept, Ewart says that gaining 1,000 feet is roughly the climate equivalent of driving 300 miles north at the same elevation. This means going from Fresno (elev. 325) to Badger Pass (elev. 7,200) feels kind of like driving north 2,000 miles, which would put us in the middle of Canada.
“So let’s keep walking in Canada,” Ewart jokes.
“If we’re walking in Canada,” someone asks, “then how far is the North Pole?”
As we slog ahead, Ewart describes how various forest inhabitants survive the winter.
Trees, he says, are protected from freezing by the high-concentration of sugar contained within their sap. Fir and pine trees, which comprise most of the Sierra forest, can withstand temperatures down to 40 degrees below zero.
The way animals survive is even more fascinating. According to Ewart, they either hibernate (like ground squirrels, marmots and most bears), migrate to lower elevations (like deer and birds) or possess the ability to tough out the elements.
Those that tough it out spend most of their time inhabiting a 1-inch thick zone between the ground and snowpack called the subnivean space. These critters move under the snow for protection from heat loss and predators, though some predators are small enough to spoil the party.
To help illustrate his point, Ewart removes a series of preserved animals from the inside pocket of his jacket. First there’s a mouse, which mainly eats seeds. Then, a mole, which eats insects, worms and grubs. Finally, a gopher, which digs into the ground for bulbs and roots.
“It’s like they’re living in the same home but dining at three different restaurants,” Ewart says.
Before we head back, the ranger stresses the importance of the 8-foot deep snowpack we’ve been trudging through all day. Without it, we’d have nothing to recharge our reservoirs or irrigate our crops.
“The way I like to think of it is that we’re standing on top of California’s economy,” Ewart says.
Even a romantic like Thoreau would have to agree with that.
