Meteorologist Stephen Bowers loves Colorado weather so much he made a documentary about it

GRAND JUNCTION, Colo. (KJCT) - Colorado’s Western Slope, we call it home. Many of us were born and raised here. Others, like me, happened upon the Western Slope along the course of life.

The weather here is varied. We can get cold in the winter and quite warm in the summer. But we’re not as hot, or cold, or as stormy as the rest of Colorado. We’re highlighting some of the facets of Colorado’s weather, and we’ll bust a few myths along the way.

Deserts

We’ll start with this thought that we live in a desert. Did you know there’s only one climate station in all of Colorado that qualifies as a desert? It’s not in Grand Junction. It’s actually the National Weather Service station in Alamosa in southern Colorado. The desert classification is actually mathematical. There’s an algebra equation that’s used that compares annual precipitation, annual evaporation, and a component called the precipitation threshold

Grand Junction is considered semi-arid. Still, we’re awfully dry, until so-called monsoon season. But that’s another myth to dispel, despite what many of us have long heard, we don’t have a monsoon in Colorado.

What Makes a Monsoon

It’s just our summer rainy season. It’s a monsoon only in the sense that we’ve decided to call it a monsoon. Maybe more completely, we have a quasi-monsoon. But a true monsoon involves both a rainy season and a dry season. So what is a monsoon? It’s not heavy rain, but a monsoon can cause heavy rain. The most textbook perfect example of a monsoon happens over India. A monsoon, in its simplest definition, is a seasonal wind reversal. In the summer, India gets hot. The hot air rises over the Indian subcontinent, and humid air rushes inland from the Indian Ocean. That humid air starts rising with the heat, and it rises up the south-facing slopes of the Himalayan mountains. In the winter, the opposite happens.

The warmer air over the ocean is rising, and dry air rushes down from the Himalayas, leading to a dry season over India. From that visual you can see we really only get half of a monsoon. More like a quasi-monsoon, than a true monsoon. In Grand Junction, an average of about nine inches of precipitation falls in a year. Most of that water is from about a foot and a half of melted snow. Not summer precipitation. Where a true monsoon happens, it’s all about summer precipitation. Mumbai, India gets huge amounts of rain from their summer monsoon. How much rain do they get? They average more than 87 inches of rain in a year. That’s more than seven feet of rain.

Monsoon or not, the storms here get heavy. That leads to more issues we experience over Colorado from flash floods, to lightning, and even tornadoes.

Flash Flooding

Flash flooding often targets mountains, and especially canyons in our state.

There’s a reason we make a big deal about the flooding. It’s deadly. More than 500 people have been killed in floods and flash floods in Colorado since 1864. Floods in 1904 and 1976 each resulted in more than 100 deaths - nearly half of the state’s flood fatalities on record.

That second flood was in the Big Thompson Canyon near Estes Park. Nearly 150 people died when a thunderstorm dumped about a foot of rain in just six hours over the canyon. The rush of flood water along Highway 34 through the Big Thompson Canyon destroyed hundreds of homes and motorists couldn’t outrun the flash flood. It’s the single deadliest flood in Colorado history.

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