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Clouds over Oregon's High Desert
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Editor's Notes
- Location: Beaty’s Butte looking west Picture-perfect clouds! These are cumulus humilis clouds—the “humble” cumulus cloud, one that is wider than it is deep. Each of these clouds is the sign of a successful thermal—a parcel of moist, rising warm air that has risen from the sun-warmed earth. As each thermal rises, it cools and, at a certain altitude (known as the condensation level), the mass of invisible water vapor molecules in the thermal condense into liquid water and become visible as a cloud. The flattened, grayish bottoms of cumulus humilis mark the condensation level where this magical transformation happens. These particular cumulus clouds are known as “fair-weather cumulus” and indicate stable air that will suppress further growth. If fair weather should turn foul, these humble clouds will broadcast this news to cloud watchers: the clouds will develop through a predictable sequence into larger cumulus mediocris (clouds as tall as they are wide) then cumulus congestus (clouds taller than they are wide) and then cumulonimbus.
- Location: Hart Mountain, SE view. The gray, flat bases of these cumulus clouds indicate the altitude at which the invisible water droplets in the atmosphere (the vapor) cools and condenses into liquid water droplets. Cumulus clouds form at this level—below 6,500 feet—and grow taller from their bases. “Cumlulus” is the Latin word for “heaps” and the word “cloud” is derived from the word “clod.” Can you see why? Cumulus clouds like these—the fair-weather cumulus—are one of the most popular and photogenic. To make your cloud photos stunning like this one, be sure to include a swath of the landscape in your photograph—1/4 to 1/3 earth makes a pleasing, balanced composition.
- Location: Black Butte from Pilot Butte The sky rarely holds just one type of cloud. Here, Black Butte is visited by at least three types of clouds. Stratocumulus clouds. “Strato” means “layered” and “cumulus” means “heaps.” Stratocumulus is a low cloud—its base being below 6,500 feet. You could probably guess this by noticing that the cloud is practically sitting on the top of Black Butte, which rises just 3,076 feet above the surrounding landscape. Knowing the elevations of your local landmarks really helps with cloud identification. The clouds that appear “behind” the stratocumulus here are actually floating above them--between 16,500 and 45,000 feet above the ground. These high clouds are both cirrostratus and cirrocumulus and are composed of ice crystals, not water droplets like the lower stratocumulus. “Cirro” means “wispy” in Latin and “stratus” means “layer.” Therefore, cirrostratus are wispy layers. Cirrocumulus are “wispy heaps.” Clouds are classified by shape and altitude—low, mid-level, and high—with the height of the cloud being the measure from the ground to the cloud’s base (or bottom). The clouds in our atmosphere are found between ground level and about 45,000 feet above it—more than 8 miles of meteorological magic to enjoy.
- Clouds are static in photographs (of course) and may seem static when we glance at them quickly in nature, but clouds are dynamic phenomena—developing, maturing, and dissipating more quickly than we ever imagine. The lifespan of a cloud is usually less than an hour. This cumulonimbus cloud is nearing the end of its life. How can we tell? Cumulonimbus clouds develop in predictable stages—from the small, cumulus clouds (the iconic lobe-shaped cloud) to the much larger, more mature “cauliflower” shaped billowing ones. You can see evidence of the “cauliflower” in the upper right portion of this photo. When the cumulus congestus reaches a certain high altitude, the water droplets in the cloud freeze and begin to spread out and give the cloud top an anvil shape (visible here in the center-left of the cloud top). Though this clouds base may be below 6,500 feet, it’s icy top could be near 45,000 feet. Were you to be watching this cumulonimbus in real time, you would see it disappear before your eyes as it snows and rains itself out from its base. Much of this precipitation will evaporate before reaching the ground--a cloud feature known as “virga.”
- Location: Shirk ranch Guano Valley looking west Weathering more than a century of storms, the historic Shirk Ranch bunkhouse stands witness to perpetually dynamic skies of the Oregon high desert. Here, the mighty cumulonimbus cloud unleashes a curtain of rain from its base and an outburst of ice from its top. The quality of this cloud top—described as wispy or fibrous--makes this particular cloud a cumulonimbus capillatus, “capillatus” being the Latin word for “hair.” Distinguish this from the tight, cauliflower-like top of the cumulus congestus cloud (on the horizon in the far right in the photo). This younger cloud may morph into a full-blown cumulonimbus before the sun sets. Both clouds are reflecting the “red” wavelengths present in sunlight. These long red wavelengths can penetrate the thicker portion of the atmosphere when the sun angle is low. The shorter blue wavelengths get scattered higher in the atmosphere to create our blue skies.
- Falling streaks of snow obscure the clouds that produced this “virga”—precipitation that evaporates before it reaches the ground. This dramatic photos shows a mix of snow virga and, where it is smoothed out, rain virga (snow that has melted into rain). Are virgae clouds? Not exactly. Virgae fall from the base of clouds—though the distinguishing between the base of the cloud and what is falling out of it can flummox even the most experienced meteorologists. The World Meteorological Organization, which is responsible for classifying and naming clouds, refers to virga as a “supplementary features” of a cloud.
- Location: Hart Mountain looking NE. While most of our cloud types are capable of precipitating, cumulonimbus and nimbostratus bring us most of our rainfall. The Latin word nimbus means “rain.” Cumulonimbus are heaped clouds and tend to form, storm, and dissipate quickly; nimbostratus are layered clouds that move in more slowly, rain steadily, and often overstay their welcome. The clouds in this photo (to the northeast) appear to be cumulonimbus, both actively raining in the distance and perhaps older “rained out” ones in the foreground. Interestingly, what these clouds are producing—rain—is actually snow melting on its way down from the inside of this deep cloud. The bright sunlight in the foreground and on this tee-pee suggest the sky is clear to the southwest. Knowing which way the storm is moving will help you decide whether to seek shelter or look forward to clearing skies.
- Bright flashes of lightning illuminated distant cumulonimbus clouds and a shelf of stratocumulus clouds over the Alvord Desert. Lightning is the visible flow of negatively charged electrons from the base of the cloud toward the positively charged ground. Most lightning strikes occur within and between clouds, while only about 20 percent occur between the cloud and ground. The dark streaks are rain, which may reach the ground or evaporate before reaching the ground. Cumulonimbus is the “Tyrannosaurus Rex” of the ten main cloud types. t’s Latin name is derived from two words—cumulus meaning “heap” and nimbus meaning “rain.” Its base is low—typically below 6,500 feet above the ground—but its top can reach over 45,000 feet. The stratocumulus cloud is also a low cloud, but as its “strato” name implies, is a layered cloud and does not have the depth or produce the lightning for which cumulonimbus are famous.
- Location: Guano Valley looking east. Sometimes it’s the lack of cloud that makes for all the drama in the skies. Here, a layer of stratocumulus clouds are blocking most of sunlight and their long shadows are cast on tiny particles of dust, smoke, or haze floating in the atmosphere to create this atmospheric phenomenon known as “crepuscular rays.” The word “crepuscular” describes something that occurs or is active at twilight (such as your cat). These rays appear late in the day when the sun is at a low angle near the horizon and shines through a thicker portion of the atmosphere. The bands we are seeing here are light passing through adjacent to the shadows of the clouds.
- Location: Steens Mountain…sunset with infrared camera. NOTE: This is the same caption as the other crepuscular ray photo...probably good to use one but not both. Unless you want to pair them as downward and upward streaming rays (in which case use the second caption). Sometimes it’s the lack of cloud that makes for all the drama in the skies. Here, a layer of stratocumulus clouds are blocking most of sunlight and their long shadows are cast on tiny particles of dust, smoke, or haze floating in the atmosphere to create this atmospheric phenomenon known as “crepuscular rays.” The word “crepuscular” describes something that occurs or is active at twilight (such as your cat). These rays appear late in the day when the sun is at a low angle near the horizon and shines through a thicker portion of the atmosphere. The bands we are seeing here are light passing through adjacent to the shadows of the clouds. Crepscular rays don’t always shine ”down” from the clouds. Here, because the sun is lower in the sky than the previous photo), the rays appear to be shining upwards from a point on the horizon. In both photographs, the rays are not actually radiating out in a fan shape. The bands of light and shadow are, in fact, parallel to each other. Only because of our perspective (making distant objects on the horizon seem smaller) do the rays appear to fan out. You can easily observe this same phenomenon looking down the parallel lines of a railroad track.
- Location: East side of the Cascades from Pilot Butte. [Lace—I am guessing this is Black Butte?] There are times when cloudwatchers should simply be awestruck and just gawk. This is one of those times. The clouds here have outdone themselves. Starting at the lowest clouds and moving up, there is a skirt of low, clumpy cumulus humilis (the heaps of humble clouds) gathered around the snow-clad Black Butte and a banner cloud drifts off its peak. Downwind of the peak and higher above it, altocumulus lenticularis (nicknamed “lennies”) hover in a stack formation and also as individual silvery lenses (lenticularis means “lens-shaped” in Latin). Lennies often form downwind of peaks of mountain ranges such as the Cascades and Sierras. The clumpy, ragged cloud beneath the stacked lennie is a puzzle to me. My go-to meteorologist (who lives in the Arizona desert) took a look at this photo and suggestd it might be a “rotor cumulus fractus”, a small cumulus cloud with a flat top and a ragged evaporating bottom (a new cloud for me!). Behind this formation in the photo are the smooth gray altostratus (mid-level layer cloud) and, above that, brighter cirrostratus (high layer cloud). A truly awesome high-desert skyscape!
- Location: Oregon Badlands Wilderness looking north. Imagine a sunset or sunrise without the clouds! One of the most important things for cloudwatchers to remember is that pure sunlight is white but is composed of “all the colors of the rainbow.” The water molecules and ice crystals in clouds do a truly spectacular job at scattering that sunlight so that we see its component colors red, orange, yellow, green, blue, indigo, violet—colors you learn in grade school by the acronym ROY G. BIV). When the sun angle is low in the sky, the sun’s longest wavelengths are most successful at passing through the lower portion of our atmosphere and an abundance of small particles—dust, haze, pollen, smoke, pollutants, for instance. When these “warrior wavelengths” as I like to call them reach the clouds—high cirrus clouds in this photo—those longer red, orange, and yellow wavelengths are reflected to our eyes and we have sky bling in the Badlands.
- Location: Hart Mountain (October)…view into north Warner Valley from Hart escarpment, ground level clouds rising and clearing after overnight/morning storm. Fog is a clunky name for a cloud—especially one so delicate and ethereal as these. Fog is a type of stratus cloud that forms at ground level. Like all clouds, fog forms when warm, moist air cools. Often that cooling is done when the moist air comes in contact with the ground (and/or water), which is why lakes, ponds, rivers and their valleys are common places for fog to form. We might say the fog in this beautiful photograph is “lifting” or ”burning off,” but it is doing neither. Fog evaporates from beneath as the sun shines through the clouds and warms the earth and water beneath the fog. That warming causes the liquid water that we see to evaporate—or change to vapor, which we cannot see. When the fog no longer reaches the ground, it is referred to as stratus. Here, you could even call it stratus fractus—fractus meaning “broken.”
- Location: Alvord Desert Playa. Altocumulus clouds are a mid-level cloud (6,500-23,000 feet above the ground) and are one of the most varied of the ten official cloud types. This one—beautifully warped by the panoramic view—is an altocumulus lenticularis, a smooth, “lens-shaped” cloud, nicknamed “lennies.” On the right of the photo you can see a small pile of lennies, which is how these surreal clouds often appear over peaks and mountain ranges, such as the Cascades. They are, as you can easily imagine, the clouds that started the U.F.O. craze. Above the gray-shaded lennies is a higher layer of cirrostratus—a smudgy kind of cloud composed of ice crystals. No matter how strange or strangely warped the clouds you observe are, capturing their reflections in still water creates a doubly compelling photograph and may inspire your own reflection: How could these two forms of water—basic H20—look and act so very differently?