Friday 4 October 2019

Thunderstorms in the Colorado Rockies

A storm approaching the Rio Grande Pyramid

Thunderstorms are scary. At least they scare me when out in the open. I knew that in summer they occur regularly almost every afternoon in the Rocky Mountains in Colorado and that it’s wise to be over any high places by noon. As the number of storms tails off as autumn approaches I hoped that by starting in mid-August I wouldn’t encounter too many of them. And initially it seemed as though they wouldn’t be a problem at all. Apart from a few distant rumbles of thunder and some dark clouds on the second day for nearly three weeks there was no sign of any storms. September came and I thought the threat was over. In fact, it hadn’t begun.

To leave the trees or not?

I was crossing open ground below San Luis Peak, a fourteen-thousand-foot peak I was considering climbing, when dark clouds rushed in and I heard the first rumbles of thunder. Thoughts of an ascent vanished and, as I wrote in my journal, ‘I scuttled over the high points pretty quick.’ There was thunder the next day too, and the one after that. In fact, it was stormy for eight of the next nine days and the thunder didn’t just occur in the afternoons and clear quickly. I had one storm at 8 a.m., just as I was setting out, and one at 6 p.m. as I was looking for a camp site. Others happened anytime during the day. 

Twice lightning flashed in front of me with thunder crashing barely a second later. Once when I was about to leave the forest for a high pass. I stayed in the trees until the thunder was fading into the distance. The second occasion was really frightening. The day was already stormy with a strong wind and rain and cloud down on the summits. As I climbed the rain turned to stinging hail.  I was following a narrow trail winding its way up a steep rocky ridge and was enveloped in the mist when a flash of lightning shot across the slope in front of me and deafening thunder cracked overhead. Without pausing to think I turned and ran back down to where the ridge broadened and I could drop down the side to  a shallow bowl, which probably offered little protection, but which felt safer than being on the ridge itself. I moved away from my trekking poles and sat on my pack. A flock of ptarmigan fluttered away. I could have been at home in the Cairngorms. After maybe half an hour the storm had moved away and I set off again, crunching nervously through the hail.

After the storm

Other thunderstorms stayed further away but were still unnerving, especially on the three-and-a-half-mile crossing of the vast plateau called Snow Mesa where there’s no shelter other than a few willow bushes in some shallow stream beds. I did sit in one of these for a while when the thunder seemed too close for comfort.

On Snow Mesa

During these days there was rain too, sometimes many hours of it, and my waterproofs, dead weight for nearly three weeks, were now essential. Much of the route is above the trees here and even when there was no thunder the rain and clouds made me feel edgy, constantly watching for lightning and looking for possible places to shelter. I walked fast too, partly to keep warm in the wind and rain, but also because the mountains no longer felt safe.

The nervous tension, the fear, the cold and the rain brought rewards though. The light was often startling and magnificent as the clouds towered up, lit by the sun. Several times I saw impressive mammatus clouds, very distinctive and spectacular but usually found with unstable cumulonimbus clouds, bringing thunder and lightning, strong winds, and hail. Seeing these clouds when far from any shelter really made me feel small, a tiny vulnerable dot in a vast mountainscape. 

Mammatus clouds

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