There is something so refreshing about a summer rainstorm as it cleans the air of dust and pollen, cools the ambient temperature, and creates a fragrance of sagebrush that perfumes the air. These storms provide welcomed relief from intense summer temperatures but even every cloud with a silver lining can have a dark underbelly.

Look closely at the towering thunderheads that seem to innocently form during a mid-summer day. First there are the scattered mounds of snow-white cumulus clouds which seem to gradually materialize out of the clear blue sky. As the warm, moist air which defines these clouds continues to rise, the thunderhead or cumulonimbus cloud continues to grow. Within the developing cloud, this warm and moist air begins to cool at higher elevation forming hail or semi-frozen water droplets. Circulating downdrafts inside the cloud carry these heavier droplets downwards from perhaps a height of 75,000 feet or more.

Within the thunderhead, the downdrafts of cooler air slide past updrafts of warmer air and this cycling of air and moisture, along with heat given off by the collision of the water or ice particles, creates a charged environment of positive ions higher up in the cloud and negative ones lower down. When a huge amount of charge builds up, and the moving cloud draws up positively charged particles from the ground, lightning can occur accompanied by rain or hail.

During summer, the weather forecast tends to remain constant: Chance of afternoon or evening thunderstorms. Along with the electrical storms comes the possibility of rain, sometimes as a brief shower and at other times a deluge. It’s the deluges that can be the most concerning because of the resultant flash floods.

The power of moving water is a beauty to behold, albeit from a safe distance. The hardened desert surface doesn’t allow for much rain to be absorbed into the ground; instead, it saturates surfaces, then begins to runoff.

As the water collects in small rivulets, larger washes, canyons, and other drainages, it’s like having a thousand springs feeding a single tributary. And moving water seeks the path of least resistance; hence, debris and unfortunately wildlife may be caught up in its path. Just look at the piles of wood wrapped around cottonwood or willow trees in a canyon bottom, materials left from a previous flood episode, to gain a sense of the potential size of these floods.

One challenge, and one that I have been a recipient of several times, is when storms occur farther away or higher up in elevation from your location. Flash floods are appropriately named as they can appear suddenly with little or no warning, exploding through a canyon or causing a river to swell and rise sweeping away any unsecured boats. The old adage, “never sleep in the bottom of a canyon wash in summer,” is to be well respected.

During or after a hard rain, waterfalls may appear, especially along the Colorado River upstream along Highway 128 or downstream along the Potash and Kane Creek roads. These waterfalls result from the great expanses of slickrock that extend beyond the canyon walls, where there is little soil to absorb the rain. Spectacular in their own right, just beware of the potential for rockfall or the flood waters carrying debris. In the old days before the River Road was paved and culverts were installed it wasn’t uncommon for travelers to become stranded between some of the creek crossings during a flood event.

Though there is a lot of beauty in watching thunderstorms, lightning, flash floods, and waterfalls illuminate and scour the landscape, beware the dark underbelly of these events and seek safety where appropriate. Heed weather forecasts and the cautions of locals who have experienced the wrath of these storms. Warning signs at overlooks such as Dead Horse Point or Sipapu Bridge which read, “Do not stand here during electrical storms,” are not just cautionary tales but borne from tragedies.

Here are a few recommendations to remember when outside during thunderstorms:
Seek safety inside a building or vehicle when thunder or lightning occurs.

Seek higher ground during a flooding event; avoid trees or high points during electrical storms.

Hike earlier on monsoon days and be out of canyons or off the mountains before the storms roll in.
Don’t try to drive across a wash in flood.

Pay attention to changing weather and review forecasts on weather.gov