Hikers, anglers must be wary of flash floods on western Colorado rivers
An angler seeking some insights to river and fishing conditions around the state can do worse than consult the various stream-flow gauges measuring river flows around the Western Slope.
Whether maintained by the state or the U.S. Geologic Survey, the gauges offer rapid if not instantaneous responses to nearby weather events affecting water flows and conditions.
This corner regularly monitors state and federal gauges, and during the last week that online snooping revealed some remarkable changes in water levels that otherwise might have gone unnoticed.
Most gauges jumped on July 18 or 19, reflecting the passing of several fast-moving storm cells that dropped heavy rain across the Western Slope.
The Eagle River, for example, jumped from around 420 cubic feet per second at midnight July 18 to more than 700 cfs less than six hours later after an evening storm pounded the upper Eagle River Valley.
The river, once the flood had passed, was back to under 400 cfs Monday.
Likewise, the Colorado River near Glenwood Springs, reflecting the earlier passing of the same storm that hit the upper Eagle, spiked from around 2,250 cfs on July 18 to 4,000 cfs in a few hours, wobbled around 3,000 cfs for the next day and then dropped back to its “new normal” low flows of 2,000 cfs.
Similar and equally intense spikes were seen for the East River near Almont, the Gunnison River at Delta, Roaring Fork River at Glenwood Springs and the Yampa River.
What this means for the anglers or rafters or rafter/angler headed for a day’s wade or float trip is a pocket guide to fishing conditions.
For instance, even though the flows on the Colorado River had dropped to manageable levels by Sunday afternoon, it must be remembered those earlier storms swept across the soft clay and shale soils around Dotsero and State Bridge.
Although it would have been possible to fish the mid-reaches of the Colorado on Sunday, it wasn’t probable because the muddy water still was thick and chewy, not quite what you would want to float a dry fly over.
Of bigger interest, especially to those whose casual wanderings take them into steep canyon country, is the sudden onslaught of rains that may trigger flash floods.
It’s curious that desert rats, often far from any water holding fish, pay more attention to the weather events upstream than do anglers.
Those who spend days and weeks in the normally dry canyon country of southwest Colorado, southeast Utah and elsewhere know well to plan for the unseen dangers that may be bearing down on them while trapped in a canyon with no easy exit.
A cloudy sky over Utah’s Boulder Mountain is a warning to hikers downstream in Capitol Reef National Park to prepare for a quick evacuation or be ready to swim.
The same is true for such angling paradises as the Black Canyon of the Gunnison. A flash flood on Aug. 19, 2010, estimated at more than 2,000 cubic feet per second, pushed through the canyon shortly after a fast-moving storm crossed the region.
Edd Franz, outdoor recreation planner for the Gunnison Gorge National Conservation Area, said he went into the canyon less than a week after the storm to assess the damage.
“There was a lot of impact from the storm,” Franz said in an interview with The Daily Sentinel. “A couple of campsites in Ute Park were really affected by debris, and Boulder Garden Rapid was significantly changed.”
What’s extremely lucky is that no one was trapped in the fast-moving flood, which would have been extremely difficult or impossible to escape.
“We figured it went from 600 (cfs) to 2,000 in about 15 or 20 minutes,” said Ben Olson, manager for Black Canyon Anglers near Austin. “It was pretty serious.”
Last week, the stream-flow gauge for the Gunnison River at Delta showed two spikes July 18, the first going from less than 800 cfs to about 1,150 cfs and the second peaking at nearly 1,400 cfs, all in the space of a few hours.
So far, no reports of any flood damage have surfaced.
In these years of drought and low water flows, when many of our favorite rivers and streams are at rock-bottom levels, it’s good to remember Mother Nature always has a trick up her sleeve.