Crews clear rockslides, rain increases threat

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SALT LAKE COUNTY -- For the second day in a row, Utah is being pounded by wet weather, and it's causing a few problems in the canyons.

The Salt Lake County Sheriff's Office has been busy during the past 24 hours. With the recent amount of rain came rockslides.

Deputies have been busy cleaning up rockslides and doing avalanche control Wednesday morning in an effort to keep those in the area safe, but they say there is only so much they can do.

The roads in Big Cottonwood Canyon are wet but otherwise clear at this point. Salt Lake County sheriff's deputies say as the hillsides continue to take in the moisture throughout the day, driving in the canyons will become more dangerous.

Salt Lake County sheriff's Sgt. Travis Skinner said, "The canyons are unpredictable all of the time, we try to add a level of predictability to it, but you are always going to have hazards."

Canyons are dealing with mudslides, falling boulders, avalanche control, even streams that typically look pleasant this time of year now flowing at rapid speeds.

"Unfortunately, Mother Nature is unpredictable, and so you really have no way of knowing for sure that the roadway is always going to be safe," Skinner said.

A rockslide Tuesday night near Gulch in Big Cottonwood canyon scattered nearly 50 boulders across the road.

Deputy Andy Arnn, with the Salt Lake County Sheriff's Office, said, "There was a few rocks in there that was approximately the size of a chest freezer."

Todd Nerney lives up Big Cottonwood Canyon. He said, "I've seen mudslides but never big rocks rolling down when I've been standing here like this."

A rockslide was also reported in Emigration Canyon Wednesday morning and several smaller ones could be seen in Parley's Canyon as well.

Geologist say several factors cause rockslides: high groundwater levels, the freeze-thaw phenomenon and downpours. Francis Ashland, with the Utah Geological Survey, said, "When you have an intense rain storm, we're having erosional events. Some of those can cause minor landsliding, or debris can be washed down slope and that can look like a mudflow."

Keith Brown, Head of UDOT's Geotechnical Division says runoff and a freeze-thaw cycle are also destabilizing some slopes.

Brown says crews constantly check the hillsides for signs of instability, but he says in most places, drivers simply have to watch for the road signs. "A familiar sign on the side of the roadway is the rock fall warning sign. And any time those signs have been placed they do identify areas that have been prone to rock-fall," Brown said.

Deputies say slides are fairly typical this time of year and say they are doing everything they can to warn drivers about dangerous spots, but they say, just like the weather, it can be unpredictable and potentially fatal.

"We have had fatalities from big rocks coming down on the road, so definitely a hazard, something to be aware of and watch out for," Skinner said.

Sgt. Skinner says storm drains are also a hazard right now. He says if the drains get blocked by debris, it will cause flooding and that can potentially cause the road to become unstable and break down.

"UDOT goes up and down the canyon frequently, we uncover the debris from the storm drains, we check the roadway, and we usually mark the hazards as fast as we can. And get them fixed as soon as we can," Sgt. Skinner said.

UDOT handles many of the areas along highway corridors. The Utah Geological Survey handles other areas prone to landslides.

Geologists say the rain does have them monitoring areas in the past where land has moved, including Spring Hill Drive in North Salt Lake, a slide that's moving about 40-50 inches a year right now has already claimed two houses.

Scientists say recent rain could make a muddy mess, but they don't expect the moisture to significantly speed up the slide's progress.


This story compiled with contributions from Shara Park and Marc Giauque.


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