Seasons and Weather|
Let's start off with the
most-asked questions: When will the rain stop?
When will the fog lift?
|Tell Me When ....|
If it's raining on the mountain, you can be 90 percent sure it's raining throughout the surrounding area. In summer, look for a Washington or Richmond paper at one of the lodges, and check the weather forecast. Or try to get a local station on your car radio at news time. As I write this, the weather forecast is posted on a bulletin board at the front door of the Byrd Visitor Center at Big Meadows. I hope that service will continue and even expand, so that during the summer season the forecast will also be posted at the campground entrance stations.
The fog is different; its coming and going can't be predicted. On the average, you can expect fog on the mountaintop two or three times a month in winter, and once or twice a week in mid-summer. The problem is that, to a large extent, the mountain causes fog. Moving air masses must rise to get over the mountain. As the air rises, it expands and cools; if the air is moist, cooling may cause moisture to precipitate as tiny droplets, and produce the clouds that we call fog. As the air descends the eastern slopes it warms, and the fog dissipates.
How long will this go on? A morning fog will often lift before noon, as the air grows warmer. But "often" can't tell you when this fog will lift. I have no statistics on fogs and how long they last. The following figures are guesses, based on my own experience as I remember it.
The chances are between five and ten percent that the fog will be gone within an hour.
The chances are better than 50 percent that it will be gone within 24 hours.
The chances are better than 90 percent that it will be gone within three days.
The chances are better than 99 percent that it will be gone within a week.
When the mountains are covered by fog, and your time is limited, my guesswork statistics are not much comfort. But visitors have found several things to do about fog:
The third alternative may help you advance to the fourth, which requires a slight change of outlook. There are no views from the overlooks, or from the mountain peaks. But the streams and waterfalls still work. Wildflowers still bloom, and the flowers and leaves are more attractive with water droplets on them. (I've heard of wildflower photographers who carry atomizers to spray their subjects with.) The rocks are still there, and their subdued colors seem brighter on a gray day. Wildlife are less timid in fog, so that you're more likely to see a fox or a deer on a foggy day. And finally, if it's a really damp July or August, mushrooms are popping up all over.
You say you can't take pictures in the fog? Sure you can. This is the time for closeups. Wildflower pictures are better with a soft and subtle back- ground than with spotty sun and shadows. And pictures of trees in a foggy woods have a certain fascination. A couple of hints: Look for moderately open woods. Compose your pictures with one or two trees in the foreground, fairly well defined, and others at various distances, fading by steps into invisibility. To record the scene as you see it, trust your exposure meter. But you might want to experiment with a one- or two-stop underexposure, for a "spooky" effect.
Half a dozen times a year, an atmospheric inversion may produce a
strange effect: fog lies like a soft white blanket on the Valley and the
Piedmont, while the mountaintop is clear. Then we look down on a "fog
ocean", with the lower peaks rising above it like islands. Several times,
from the Big Meadows Campground, I've watched a thrilling sight: a fog
ocean rises on the Piedmont side of the mountain, then flows through
Fishers Gap and spills down the western slope like a giant Niagara half a
Because of its elevation, the mountaintop has from fifteen to twenty percent more precipitation than the surrounding lowlands. The average temperature is about ten degrees cooler at Big Meadows than in the Valley, and fifteen degrees cooler than downtown Washington or Richmond. The following table gives the average temperature (in degrees F.), and precipitation (in inches), at Big Meadows (elevation 3535 feet) for a recent twelve-year period.
There you have the averages. But few days, and fewer years, are
average. The weather seems to go in cycles, so that several dry years are
followed by several wet ones, and several cool years by warmer ones. At
Big Meadows, the highest temperature during-the twelve-year period was
89 degrees, and the lowest 20 below zero. Most winters are "open", which
means that snow falls only occasionally and soon melts, so that the ground
is bare during most of the season. But every five or ten years comes a
snowy winter that raises the average. I've seen almost four feet of snow on
the ground at Big Meadows, with drifts higher than your head.
Spring comes late on the mountain. If you visit the Park at the end of March, you'll drive through springtime in the lowlands and ascend into winter on the mountain. The trees and grass. are brown. Only if you look closely, and in the right places, will you see signs of hope: willow catkins opening; coltsfoot and hepatica blooming tentatively. Not until April, when you see flowers of bloodroot and marsh marigold, will you know that springtime is irreversibly here.
In May, the green line glides up the mountain. From high points you can
look down the slope and see that trees below a certain level are a pale new
green, while those higher up are still brown. Some people say that the
green line comes up the mountain at a hundred feet a day. By which they
mean, of course, that it gains a hundred feet of altitude a day. (A hundred is
such a nice, round number. I've never heard anyone say that the green line
comes up the mountain at 30.48 meters a day.)
Summer is the time for camping, for weekend crowds, for conducted walks and campfire programs. And an unending succession of wildflowers: those with leading roles stay all summer, while bit players come and go. The days are warm, but nights can be nippy. You'll need a sweater or jacket at the evening campfire program, and a warm blanket if you're camping out. The air, which was fairly clear in springtime, is now hazy, and visibility is often limited. At times, my sketches of views from the overlooks will be worthless: they show what you might have seen if you'd come on a clearer day.
The haze has two causes. One is dust in the air combined with water vapor and, I've been told, organic compounds given off by the trees. That's the haze that makes the Blue Ridge blue, and it's been here for a long time. The earliest descriptions of views from the mountains begin, "On a clear day .... "
But now the Blue Ridge haze has a second ingredient: smog from
industry and automobile exhaust, Summer smog used to be a dirty purplish
blanket that lay on the lowlands, so that we could look down on the top of it.
Just as the green line creeps up the mountain day by day, the summer smog
line crept up year by year, and in 1976 it reached the top. I'm hopeful that as
various anti-pollution programs take effect, the smog line will recede
downward. Then once again we can say, even in midsummer, "On a clear
In September, the wildflowers
still in bloom are goldenrod, asters; white
snakeroot, and gentians. Fall colors begin to appear: first the Virginia
Creeper, and toward the end of the month the black gumboth a rich, deep
red. In an "average" year the peak of fall colors comes, so they say,
between the tenth and twenty-fifth of October. By then the leaves of the
maples are yellow, gold, and red, and maybe a little beyond their best color.
But along the Drive you see only an occasional maple, for this is primarily
an oak-hickory forest. The oaks and hickories turn dark brick-red, or a
modest dull yellow-orange, soon fading into brown. The cove hardwoods,
at lower elevations, produce a more colorful display. The crowds who come
to Shenandoah from Washington and Richmond pass brilliantly colored
trees near home before they see the subdued colors along the Drive. But
I've heard no complaints. Skyline Drive is famous for fall color and, to a
large extent, people see what they expect to see.
|Winter in Shenandoah|
Winter is special. The air is cold, and sometimes so clear that only the curvature of the earth limits your visibility. The wildflowers are dead, but real aficionados can identify their dry remains. The leaves are down, so that all the trails offer views, through bare brown branches, that you could never see in summer. The fair-weather visitors are gone; if solitude is what you came for, you needn't look very far.
You have to be lucky to arrive just after a fresh snowfall, but you can depend on ice. There are rock faces along the Drive that develop spectacular masses of iciclesfor example at Mile 39.5 in the Central District, and Mile 10.8 in the North. A trip to a waterfall is a different experience now; you may find it frozen solid. Columns of hoarfrost here and there lift the surface of the trail, and crunch underfoot as you walk.
A winter phenomenon that only the luckiest visitors will see, depends on a combination of special conditions. First we must have a thick fog, moving in a slow breeze at below-freezing temperature. The fog freezes on everything it touches, building up a thin, white, icy feather on the upwind side of every twig and every blade of grass, Then, if the fog lifts and the sun comes out while the temperature stays below freezing, you'll see a mountain range covered not with snow, not with ice, but with a brilliant white frosting of sugar.
Equally spectacular, and equally rare, is a major ice storm. Aggie
Crandall, in her campfire program "White on Blue", describes it better than
I can. Here's Aggie:
If you really want to know yourself and test your capabilities, winter is the time for it. In January and February you'll find no food, or lodging, or gasoline in the whole 105 miles of Skyline Drive. Even water is hard to get. I've said that there are frostfree faucets in some, but not all, of the picnic areas; but, for one reason or another, you may find some or all of them turned off. Rangers will still help you when you need help, provided they know about it. But the temporary summer rangers are gone; the Park is down to its permanent staff, which is small. Self-reliance is expected of you in winter. Come with a full tank of gas. Use snow tires or carry chains. Bring food, water, and proper clothing.
There's always a chance, however small, that your car will break down, or get stuck in the snow, or that its gas line will freeze. Be prepared to survive a breakdown without help. I've mentioned a temperature of 20 below zero. With a strong wind that could have a chilling effect equal to still air at 60 or 70 below. If you have a breakdown it's safer to stay with the car, which will protect you from the wind. Don't depend on the car heater, because the danger of carbon monoxide is too great.
For a safe visit to the mountaintop in the coldest part of winter, I
recommend down-filled pants and parka, and insulated boots. For camping
out you should also have a mountain tent and a down-filled sleeping bag.
Many of the larger cities have stores that sell such things. They are often
listed in the yellow pages of the phone book under "Expedition Outfitters."
Here's Aggie Crandall again: