Two complex lightning bolts strike a mesa in Western Colorado in this 1-minute exposure.
One of my favorite things about the southwest is the sheer ferocity of the thunderstorms that arrive like clockwork every summer. It has always seemed to me a particularly violent way of delivering water to the desert. Anyone who has visited Arizona, Utah, New Mexico, or Colorado in the summer knows how an apparently benign, cloud-free, blazing summer afternoon can spawn a multitude of life-threatening thunderstorms in a matter of hours. Known as the monsoon season, late summer in the American southwest is a time during which many areas can receive as much as half their annual rainfall in the span of just a few short weeks. Generated by the arrival of tropical moisture from the south, these are thunderstorms that force one to begin any summer hike involving peaks or ridges in the wee hours of the morning to avoid being caught in an unpleasant situation. These are thunderstorms that claim the lives of dozens of people every summer, sometimes via lightning strikes, but more often via sudden deluges of water known as flash floods that result when rain falls so fast and so hard that it doesn’t have time to soak into the soil, and instead collects in raging torrents of water, mud, trees, and rocks that can travel vast distances, sweeping unsuspecting hikers dozens of miles away from the nearest raindrop off their feet. These are also storms that produce truly unforgettable memories (the fondness of which is directly proportional to how close shelter is at the time…) and great photographs, again assuming adequate shelter is close at hand.
Storm clouds begin to swirl during a late evening monsoon thunderstorm.
Perhaps most mercifully though, these are the storms that ultimately temper the stifling heat that dominates the southwest early in the summer. Ironically, this oppressive heat actually brings about its own demise; the intense heating of the land surface in the early summer (May and June) is responsible for causing the monsoon rains that eventually bring temperatures back down to somewhat more humane values by late July and August.
A pair of lightning bolts; one cloud-to-ground and one cloud-to-cloud.
Two words are all one really needs to fully describe conditions in the American southwest in the early summer: “hot” and “dry”. Temperatures soar well into the 100s in many locations and relative humidity values in the low single digits are commonplace. As anyone who has ever lived on the 2nd floor of a poorly ventilated apartment building in the southwest in the summer knows: hot air rises. This basic thermodynamic fact can be used to explain just about every aspect of what is formally known as the North American Monsoon, or any monsoon, or just about any form of weather for that matter. As the Sun heats the land surface, warm dry air begins to rise high into the atmosphere due to its lower density. This rising air column leaves a void, a sort of a partial vacuum if you will, behind it, creating an area of low atmospheric pressure over the sizzling southwestern states. This partial vacuum creates a welcoming pathway for warm, moist air from the tropics to slowly begin seeping its way north from Mexico and the Gulf of California. As the month of June comes to a close, this tropical moisture has begun to saturate the air around the Four Corners region. Gone are the days of single digit humidity values, and by early July, the Sun, instead of heating bone-dry air, is heating air that is rich with moisture.
Large cumulus clouds, the infant stages of a monsoon thunderstorm, hover over Colorado’s highest point, Mt. Elbert. Clouds like these are a sign to hikers to get off the mountain and start heading for shelter; a scene like this can develop into a full-blown severe thunderstorm in as little as an hour.
Now when moist air rises, the water within it condenses into water droplets, first creating puffy cumulus clouds, and eventually enormous cumulonimbus thunderheads that can reach heights of more than 50,000 feet above the Earth’s surface. These storms normally develop in the afternoon, after the Sun has had several hours to warm the surface and generate a robust rising column of air. To give you an idea of just how fast these storms can expand, and since WordPress won’t let me post videos, here’s a fun little animated GIF showing about 15 minutes of growth in a late evening thunderstorm over the West Elk Mountains of Colorado. Notice the stars in the background:
While the annual arrival of the monsoon may be predictable, the individual storms that it produces are not in the slightest. The isolated nature of the storms can be incredibly surreal; I’ve been in locations where 2″ of rain and nearly a foot of hail fell in a matter of 30 minutes, while the ground half a mile away remained completely dry. And while the North American Monsoon may not pack quite the same punch as its southeastern Asia cousin, it nevertheless is a significant event, in both negative and positive ways, for all who live in the area. Good in that it provides the southwest with badly needed moisture in the late summer, and bad in that its unpredictable nature never fails to catch those unfamiliar with the weather pattern off guard. In addition, storms during the first few weeks of the monsoon will often generate copious amounts of lightning, but very little rain, sparking numerous wildfires in tinder-box dry forests that haven’t seen rain in months, fires that are nearly impossible to extinguish until heavier rains arrive to douse the flames.
Photographing these storms is most easily accomplished at night, when you can simply point the camera at the storm (provided you and your metal tripod are somewhere reasonably safe), leave the shutter open for a few minutes at a time, cross your fingers, and hope for a few well placed strikes. While the best bolts inevitably occur in the two seconds your camera is processing your most recent exposure, or are located juuuuuuuuuust outside the camera’s field of view, rest assured that the light show that nature puts on will still be exponentially better than anything you could possible see on your computer monitor or TV screen.
The crest of a large thunderhead stops just shy of obscuring the Big Dipper.
My college English professor once told me that a great way to hook people on a story is to begin with a personal anecdote. Though now that I think about it, he also told me that bacon was bad for me and that my writing was good, so I suppose I should take anything that came out of his mouth with a grain of sodium chloride. But heck, I’m even prefacing the primary anecdote with this secondary anecdote so you should probably just read anyways.
Let me set the scene for you: Bellingham, Washington; nestled along the coast where the Strait of Georgia and the Strait of Juan De Fuca merge together to form a bewildering assortment of coves, islands, bays, and inlets, where half the license plates you see on the highway are from British Columbia, in the only place where the occasionally explosive Cascade Range makes its way allllllll the way down to the beach, and where the nearly 11,000 foot ice sculpted summit of Mt. Baker dominates the view from town on 100% of the 25% of the days out of the year when there is actually a view from town. (Read that again if you need to…) You see, Bellingham is really cloudy. It also happens to be where I currently reside. I’m not trying to knock Bellingham; it’s a great town in a myriad of different ways. Really great. The pictures on this page should prove that. But it’s really, really, REALLY cloudy. Especially in the winter. When I first got here I had a professor tell me that a sunny day is a perfectly legitimate excuse for turning in an assignment late. Many days I wake up, open the blinds, and think that I must be watching an old episode of Gilligan’s Island…you know, the one’s before they started making it in color? In fact, the official motto of Bellingham is “The City of Subdued Excitement”. I am convinced that this is mainly because it’s a little hard to be anything other than subdued when a gray pall can settle over the city for weeks on end. It’s like nature’s Vallium.
Anyways, the anecdote. Upon the advice of professors, students, and other acquaintances familiar with the winter…er…”conditions”…here, way back in September (one of only three months out of the year where it is statistically more likely to be partly cloudy or sunny than completely overcast) I made a visit to Rite-Aid with the intent of purchasing some Vitamin D tablets. Now let me assure you that the vitamin section at Rite-Aid is the very epitome of robust; my local store stocks about eight different complete lines of nutritional supplement products. Vitamin A, Vitamin B, Vitamin C, Vitamin Q, calcium, magnesium, iron, glucosamine, corn silk, echinacea, fish oil, cod oil, beet juice, cow bile, pig urine extract…it was all there. Except for the Vitamin D, whose slot on the shelf belonging to each and every brand was completely empty. An omen if I’ve ever seen one.
Now that I have (hopefully) made my point, the question becomes: can we quantify just how cloudy Bellingham is? On the surface, one would think that composing a list of the cloudiest cities in the United States would be a relatively straightforward exercise. You would be wrong. It turns out that a variety of methods exist to generate such a list. One can, for example, calculate the total number of overcast hours per year expressed as a percentage of possible daylight hours (if that made any sense at all). Others prefer instead to count simply the number of days in which the Sun remains hidden behind clouds for the entire day, or the number of days in which the sky is overcast for more than 50% of the daytime hours. And none of this even begins to take into account this potentially thorny issue: what constitutes “cloudy”, exactly? Should “partly cloudy” count as “cloudy” or “sunny” in a tally? One imagines that the answer to this depends on weather the meteorologist undertaking this task is more of a “glass half empty” or “glass half full” kind of person. And what about night? Do we care if it is cloudy at night? Or are we only interested to know how much sunshine we are losing? As an astronomy enthusiast, I demand that the percentage of cloudy nighttime hours be taken into account. As you can see, madness is never that far away.
The lack of any well-established protocols when it comes to defining “cloudiness” leaves ample opportunity for cities who rank highly on one list to try and come up with a new way of calculating the list that moves them down a few spots. Or, ideally, out of the top 10 entirely. After all, you don’t see too many glossy tourist brochures exclaiming “Come visit the 3rd cloudiest city in Washington and enjoy a vacation without the hassle of having to reapply sunscreen every 3 hours!” Catchy as it sounds, it just doesn’t sell. (However, if you happen to be a tourism exec from Aberdeen, WA and you are interested in licensing this slogan for use in your promotional materials, please contact me using the oh-so-appropriately named “Contact” link above!) Regardless of which metric you use though, Bellingham, Washington generally ranks near the top of such lists. If it doesn’t, chances are the makers of the list are interpreting the word “city” rather loosely and including every little hamlet and village on the Olympic Peninsula in their calculations, yet another devious method of getting yourself off the list.
To give you some perspective on my rant, I feel obligated to disclose that I grew up in Flagstaff, Arizona, a city that receives, on average, more than 300 days of sunshine per year. Such a concept is about as foreign to Western Washingtonians as a hurricane warning is to Saskatchewanians. The rain here is different too. During a lecture on precipitation last quarter, one of my professors asked the class, composed almost entirely of western Washingtonians, if anyone had ever experienced a “thunderstorm“. Less than half of the class raised their hands. More often than not, we experience what someone in New Zealand would call “pissing”, a steady, extremely light rain that that lasts for days and yet somehow manages to thoroughly permeate everything with dampness despite never requiring you to change your windshield wiper setting from “intermittent” to “warp speed”. However, when the rain finally ceases and the clouds part, the emotions experienced is roughly on par with the feeling that Arizonans get when it rains for the first time in months. Everyone just sort of stops whatever it is that they are doing (including driving apparently…as much as it rains here, you’d think people would be better at driving in it) and goes wandering around outside looking up at the sky, squinting, and trying to figure out what the hell is happening.
And then there’s me. While everyone else stumbles around in disbelief, I grab my camera, put on my hiking boots, and head to the nearest beach, mountain, waterfall, overlook, or trail to enjoy and photograph a majestic landscape that truly deserves to be uncloaked and put on display far more often than it is. But naturally, I do all of this in an extremely subdued manner.