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August 21, 2017

Silver Coin Gulch Deluge Blocks Lake Road July 27


 

Motorists on County Road 30 between its juncture with Highway 149 and Lake San Cristobal were delayed in both directions for several hours late Thursday afternoon, July 27, as the result of a torrential rainstorm which has been described as a microburst.
The sudden rainfall cascaded down the slopes of Hotchkiss Mountain into Silver Coin Gulch.
Described as a “wave of water” by Hinsdale Road & Bridge Supervisor Monte Hannah, the deluge brought with it tree debris, mud and gravel, carrying along some boulders the size of car engines.
As the gulch flattens out on the mountainside roughly 1,500’ to 2,000’ above County Road 30, the flood-carried rock and debris totally filled and bottlenecked Silver Coin Gulch for a distance of 100’, forcing the water out of the gulch and into several newly-formed tributaries which were created on downhill slopes to the north.
Based on terrain, much of the water rejoined Silver Coin Creek just above the county road, in the process inundating and filling a 60”-diameter, 25’-long culvert under the road and burying the road under several feet of rock, mud and debris.
From Silver Coin Gulch, the flood waters passed directly down the county road, water, mud and associated debris flowing down the bar ditch along the side of the road a distance of .03-mile to County Road 30’s juncture with Highway 149, and then continuing along the Highway 149 bar ditch another .03-mile as far as the turnoff to Hummingbird Lane at Vickers Ranch.
In addition to washing down the county road and side ditch, water from Silver Coin Gulch cascaded across the county road down the mountain to Weems Malter Placer Subdivision. No reports of damage to homes in the subdivision were reported as the result of the flooding, although a wood rail boundary fence in the subdivision was severly bowed after catching the brunt of the cascading water and debris.
Minimal damage was also reported to the 4WD road which parallels portions of Silver Coin Creek or Wally Hays’ private property which is immediately upstream from the creek at County Road 30.
Water which fanned out from Silver Coin Gulch followed gravity, the dirty, yellowish water cascading down into the Lake Fork River via Weems Malter Placer and Vickers Ranch, turning the river a muddy yellow/brown color.
Learning of the isolated flooding — and with traffic already impacted in both directions on County Road 30 — County Road Supervisor Hannah dispatched road employee Gavin McNitt on a backhoe shortly after 4 p.m. on Thursday. McNitt quickly assessed the situation and called in for additional backup, Road Supervisor Hannah arriving at the scene with a loader for McNitt, followed by Breck Thompson to take over backhoe duties, and Norman Ragle who brought a county grader down from Sherman. Shop Foreman Don Menzies hauled in the county’s excavator. Road employee Johnny Bebout, who had been on roadwork on the Upper Rio Grande, was also called in to assist locate culverts, direct traffic, and grader cleanup.
Among those assisting with the emergency cleanup was Hinsdale County Commissioner Stan Whinnery who used the county excavator to dig down to the Silver Coin culvert and excavate both ends of the culvert in order to re-establish waterflow. The culvert was buried beneath upwards of 10’ mud and rock. Obscured at such a depth, a metal detector was initially used to even locate it within the flood debris. Commissioner Whinnery references county road employees’ outstanding work, also crediting others who assisted, in a letter to the editor in this week’s issue.
Road Supervisor Hannah describes the flash flood as “horrible” and says the combined force of the water and debris washing across the road threatened to sweep away the county backhoe driven by McNitt. The force of the water was so great, according to Hannah, that McNitt called in to report that steering was impacted.
“I would not have wanted to be in front of that wave of water,” says Hannah, “it would have moved a car.”
Others responding to aid with traffic control and cleanup were Colorado Dept. of Transportation’s R.E. Hall, Randy Smart and Bruce Hillis; Tom Carl, Bruce Curry, and Undersheriff Justin Casey and Deputy Chris Kambish from Hinsdale County Sheriff’s Dept.
Upwards of 80 to 100 vehicles traveling in both directions on County Road 30 were brought to a halt as the road crew worked to reopen the county road. Traffic backup on the road extended as far up as Highlander RV Park above Silver Coin Gulch, and backed up the full length of County Road 30 in the opposite direction onto Highway 149 to the north.
Hinsdale road crew worked from just after 4 p.m. on Thursday continuously until final cleanup of the county road at 9:30 p.m. Final work on the road was completed by Don Menzies after 9 p.m. as he washed down the road surface. Road crew continued to monitor and mop up the flood impacts on Friday, July 28, when both the entrance and exit to the road culvert were once again cleared, and continuing cleanup, ditch cleaning along that section of the county road throughout this week.
Supervisor Hannah said the flash flooding did not damage the asphalt surface on County Road 30, although the road surface was already deteriorated and heavily patched. The road surface at Silver Coin has, however, been further impacted as a result of the ongoing cleanup.
Upper reaches of Silver Coin Gulch which were filled to the brim by the debris are located on BLM lands, Supervisor Haannah stating that he intends to contact the agency to determine whether 100’ or more of the chock-filled channel may be cleared to return the stream to its traditional course.
Silver Coin Gulch serves as a significant gulch funneling water off the slopes of Hotchkiss Mountain and into the Lake Fork between Lake City and Lake San Cristobal. The county road to Lake San Cristobal has historically paralleled the Lake Fork at this location and necessarily traversed Silver Coin Creek. Heavy timber remnants below the road indicate that the deep gulch was initially crossed with a timber bridge, although in recent memory dating back to at least the mid-20th Century, the creek has inconspicuously been crossed utilizing a heavy gauge 60”-diameter metal culvert. The culvert has only minor slope, however, and has on occasion become filled with gravel and mud during high water events.
Newly retired Hinsdale Road Supervisor Robert Hurd says that he can recall at least two flood occasions on Silver Coin Creek during his tenure, the first of which took place about 1987. The last Silver Coin flooding was about 1998 when, similar to last week, a large volume of water cascaded down the gulch and overflowed the road after overwhelming the culvert.
Hurd recalls that in the 1998 high water, a backhoe was used to gingerly reach into the culvert at both its mouth and exit to remove accumulated gravel.
* * *
On the heels of an apparent microburst which caused the localized Silver Coin Gulch flooding last Thursday, further torrential rains on Friday resulted in some road damage on County Road 20 from approximately the Pelican millsite up to Alpine Gulch on Henson Creek.
Excessive water caused a significant gravel slide near the base of Hidden Treasure Hill roughly 2.5 miles up Henson Creek. The slide covered approximately one-half of the road surface, in the process depositing a boulder the size of a 55-gallon drum onto the roadway.
Road employees Don Menzies and Johnny Bebout with backhoe and loader, and again aided by Commissioner Whinnery with loader, worked 2-1/2 hours on Friday afternoon clearing the gravel slide.
U.S. Weather Observer Phil Virden states that just .08” precipitation was recorded in Lake City July 26-27, although total precipitation jumped to a torrential .82” July 27-28.

 

Photos courtesy of Normal Ragle, Gavin McNitt and Grant Houston

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