Is Boulder-Like Flooding In Payson’S Future?

CLIMATE Q&A

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by Jim Speiser, Special to the Roundup

With the recent onslaught of natural disasters around the world, and increasingly dire predictions coming from climate scientists, I thought it would serve Payson area residents to present a regular column that assays to answer their questions on climate change, and how it might affect us in coming years. And so herewith I present “Climate Q&A.” My main focus will be on local effects, but as climate change is a regional, national and global concern, I will from time to time present “The Big Picture” to put our situation in a larger context.

To start off, let’s look at a recent disaster and ask — “As a mountain community much like Boulder, Colo., should we worry about devastating floods in our area, enhanced by climate change?”

Historically speaking, floods are rare in the Payson area — the most memorable exception being the 1970 Labor Day Flood, covered extensively in these pages just a month ago. (Arizona Explained: Record Floods Killed Labor Day, Aug. 20) Called Arizona’s deadliest natural disaster, that event took the lives of 23 people, mostly around the Tonto Creek area, and was the result of Arizona’s most copious rainfall ever — 11.4 inches, a record that stands to this day. That total even exceeds the Colorado single-day record of 8 inches set in the Boulder Flood (but they did receive 17 inches for the week).

Could it happen again? Could Boulder be a harbinger of things to come?

To answer this, first it’s important to consider the differences between Boulder and Payson. Boulder is much more densely populated, and thus has more infrastructure prone to disruption by raging floodwaters.

The second factor is topography: located at the eastern edge of the Rockies, Boulder and its environs are basically one big floodplain, whereas Payson is more or less on top of the mountains. These factors mitigate against a Boulder-like flood in our area.

Weather experts have a way of describing natural disasters in language that imparts the statistical odds of them recurring. They talk about 50-year, 100-year, and 1,000-year floods and rainfalls. To say that an event is a “1,000-year” flood is to say that it has a 0.1 percent chance of occurring in any given year. Both the Boulder Flood and the 1970 Labor Day Flood have been described as 1,000-year events. But such designations reflect what’s happened in the past and assume similar conditions in the future. With the onset of climate change, it’s dangerous to allow these terms to lull us into complacency — the past is no longer prologue to the future.

For one thing, a major factor in the “biblical” strength of the Boulder Flood was the proliferation of wildfires plaguing that area over the past few years. Climate experts have predicted that wildfires will be more prevalent in this age of longer warm seasons and generally drier conditions. This is as true for Payson as it is for Boulder, and our area is one conflagration away from being made more vulnerable to floods. The reason is that fire destroys the soil’s ability to absorb water, and thus rain waters slide right over it rather than being drawn into the ground.

Furthermore, the weather patterns affecting both Payson and Boulder on those fateful occasions were somewhat similar. In both cases, moist tropical air sweeping up the slopes of the mountains met with “blocking” cold fronts, resulting in the deluges. Climate experts are now predicting that patterns like this will be a more frequent occurrence, because of a new development they have their eyes on: the “stretching” of the jet stream.

The jet stream is that band of upper atmosphere wind circling the earth right around the Canadian border — or at least, that’s where it used to reside. They believe the rapid warming of the Arctic has “loosened” the jet stream so that it flops around like a fan belt that’s come off its pulley. There is no doubt that the jet stream is invading lower latitudes as never before, bringing frigid Arctic air in contact with warm tropical fronts, and this is playing havoc with the weather: the effect has been blamed for the Snowpocalypse, the Snowmageddon, and even Hurricane Sandy.

It is of course difficult to predict the future with any clarity, but taking what we do know to its logical conclusion — drier droughts, hotter warm spells, rainier rains, and wacky weather in general — it’s not difficult to see why the next 1,000-year event could happen a lot less than a thousand years from now.

Jim Speiser is a retired talent agency executive who has turned his attention to climate change. He has lived in Payson with his wife Mary since 2004.

Comments

Pat Randall 1 year, 2 months ago

Tonto Creek water will not come into Payson. It may wipe out Kohl's Ranch, Gisela, a lot of Tonto Basin and Roosevelt dam if the Salt River gets a lot of water too. It also runs into Roosevelt. The water almost went over Roosevelt Dam in the 90's only 3 inches to go and it would have gone over and the dam would have been gone then the ones on down the river into Mesa, Phoenix and on. I know the dam has been raised but Jim was talking about big storms. If you don't believe about the water in Roosevelt in the 90's do some research with B.O.R. Payson needs to worry about the houses built on the hillsides and especially the ones that have half the house hanging in space. When I was growing up in Payson the water would run down American Gulch all the way across the meadow from McLane on down thru where the golf course is. The houses just west of the lakes at Green Valley Park will be half under water or gone if we get a really big storm.

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