Leaving the Pawnee Grasslands we were listing to starboard because we had a stiff crosswind from the southeast. As we approached Fort Collins we met up with a strong and gusty headwind out of the west pushing down off the Rockies onto the prairie. These converging winds whipped up dust devils and stench across cattle feedlots forcing me to grip the wheel more tightly and downshift. Our little box on wheels can really get pushed around. Ominous thunderclouds dominated the sky and we had entered “Hail Alley”, not to be confused with the nearby “Tornado Alley”. This is a tough neighborhood.
Our ground level experience is a smaller scale representation of bigger phenomena and some of the most dynamic weather on the planet. This nice hot day on the prairie was heating up some moist air blown up from the Gulf of Mexico. As this rises to meet cold dry air rushing off the western mountains any and all chaotic thunderstorm participants can show up. Moisture rises into colder upper air condensing and building into massive expanding 40,000 ft towers of cumulonimbus thunderheads. Sheets of rain can develop, often as ethereal virga curtains across a horizon so dry that they evaporate before reaching the ground. If updraft winds are steady and strong the condensing water is held aloft in subfreezing air forming hailstones. When that vertical wind holds at over 100 mph those stones can become baseballs or bigger before they outgrow that wind and fall disastrously to earth. All this water changing states and moving through the clouds creates huge amounts of static electricity and brings some loud and flashy cohorts to the party, lightning shortly followed by his boisterous partner thunder. These are all overshadowed if a tornado shows up. The high speed winds meeting at opposing angles creates a log roll of air that when tilted vertically makes a force so devastating that we have yet contrive a sturdy enough device to accurately measure it.
With these characters in mind, we were grateful to have a cozy home to arrive at, though Nancy cautioned us that her property had twice been hit by lightning with some unpleasant consequences. I decided to go out and cover our solar panels in case those consequences included icy foul balls from the sky. Curious about the what the meteorologists had to say about all this we cut on the TV to find that the local station had preempted everything to show one of their storm-chasers tracking an active supercell a couple hours south of us. We watched live as a dark grey funnel dropped to the ground forming a tornado as our videographer wisely put his vehicle in reverse to find safer ground. The drama continued for over an hour and thankfully no one was harmed. Shutting off the television didn’t end the show with lightning flashes brightening the darkened house into the wee hours.
The morning broke to another crisp clear Colorado day. However it was warm and that brings the key player in all this. Heat is the driver of this atmospheric activity and as the wide prairie bakes in the sun that energy inspires another round of afternoon puffy clouds. I had been thinking about how the previous day all we got was wet and that maybe I should uncover the panels and put the tarp away. I guess I hadn’t noticed that the puffy clouds had brought some friends and that they had all grown up into puffy white mountains. No sooner had I folded back most of the protective covering than I heard the first metallic “clinks”. Before I could confirm that sound, something cold and hard bounced off the back of my head. I got the tarp back on and was under the cover of Nancy’s garage just in time enjoy the chaos of a hundred thousand frozen nickels and quarters pummeling the neighborhood, wild sounds of hail impacting metal, wood, concrete and asphalt, bouncing and rebounding. As they began to collect it occurred to me that this is a lot of underutilized ice. So I got a glass, a little gin and a splash of bitters. How often does one get a chance to have a cocktail served over natural ice cubes from the gods?
Springtime in the Rockies means that this is an almost daily cycle. Each afternoon mythical castles of white clouds are built up then blown away overnight. Days later in the wide San Luis valley we had perhaps the best venue for the performance. Sitting in a hot spring on the north end of the valley our stage was 70 miles wide framed by the San Juan Mountains on stage right, the Sangre de Cristo Range on the left. Fast moving thunderheads extending from the valley rim to the Jet Stream cruised across the landscape, their dark underbellies shooting white thunderbolts to the ground every few miles, alternating with the strobing purple of interior cloud lightning. With the sun dropping behind the mountains the towering clouds remain illuminated by the last rays of the day. Billowing folds of pastel pink and peach and constantly morphing domes of richer oranges and reds. All this drama could make you forget that there is still another quiet member of our party. A rainbow must always arrive as a surprise guest, pleasantly catching the corner of our eye as the last low rays of sun sneak under the clouds of a darkening sky.
Vagabond Naturalists 
