1983 was Utah’s great flood year, the year when Salt Lake City’s State Street briefly turned into a river. But Davis County was among the areas with the most extensive destruction that year. For the historic floods, yes, but also for the number of landslides and the sheer amount of damage.
In May and June of that year, the county saw over 100 debris slides, destroying homes and causing millions of dollars in damage, according to a 1989 report from the Utah Geological and Mineral Survey.
Davis County is historically one of the hardest-hit counties by landslides in the state, although Utah’s biggest slide happened in Utah County near the town of Thistle in Spanish Fork Canyon.
This spring has also been wet, and the Utah Geological Survey estimates there have been 80 recorded landslides around the state this year, with eight taking place in Davis County, according to Greg McDonald with the UGS.
While the slides this year haven’t been as damaging as 1983, the uptick in landslides can be linked to the huge amount of snow from this winter, which leads to saturated soil that can deteriorate during the spring runoff, according to a Utah Geological Survey presentation to the Utah Legislature earlier this month.
But given the high snowpack around Utah, McDonald said there have been fewer landslides this year than the UGS anticipated.
“We knew with the record snowpack this year, we were gonna have landslide issues,” McDonald said. “There have been quite a few, and we’re still responding to several, but it’s not as widespread as it has been in past years.”
The 1983 landslides
Around Memorial Day in 1983, the cool, wet weather that plagued Utah for months gave way to temperatures in the 90s, causing widespread floods around the state.
The already damp mountain soil couldn’t absorb the record snowpack, as the state had seen back-to-back years of heavy winters, further compounding the risk of landslides and mudslides.
“The snow melt just crashed. It just heated up way too fast,” McDonald said. “That caused a bunch of soils on the sides of these side canyons to become saturated and mobilize to debris slides, which then became debris flows as they entered flooding channels.”
Among the areas hardest hit was Farmington, where a landslide tore through nearby Rudd Canyon and scattered dirt and debris across nearly 18 acres of land, according to the 1989 UGS report. The landslide caused $3 million in damages to homes alone, as it leveled eight houses and damaged 35 others. The slide also caused over $1 million in damage to public facilities.
An article from United Press International from May of 1983 described the Rudd Canyon slide as “a 20-foot-high wall of mud” that forced the evacuation of the Lagoon Amusement Park. Farmington’s public works director told UPI that officials evacuated the park “because of the number of people there and we weren’t sure what the slide would do.”
In nearby Fruit Heights, 75 people were evacuated that spring after officials started to worry about a landslide in Baer Canyon. The area avoided widespread catastrophe, but the report says, “water lines, culverts, and personal property in that community were subjected to damage.”
Bountiful also suffered extensive damage. The 1989 report says two significant slides pushed debris out of Stone and Barton creeks, causing around $4 million in damages. Water systems in Bountiful were contaminated after the aqueduct that moved irrigation water to the town was destroyed.
In total, the report says Davis County suffered around $18 million in damage in the spring of 1983 due to landslides.
Years in between
Even without the record snow that helped trigger the ‘83 landslides, Davis County has seen recurrent damage from landslides over the years.
In 1998, a landslide along Sunset Drive in Layton damaged seven lots and led to a home being condemned, according to a report from the UGS. City officials studied the area’s landslide risk and later proposed building a drainage system near the edge of the slope where the homes were on Sunset Drive. However, another UGS report says, “the majority of homeowners decided not to finance the installation.”
On April 15, 2006, the same slide was reactivated. Like in 1983, the landslide could be connected to an increased amount of groundwater due to snowfall.
“A 4- to 8-foot increase in groundwater levels between March 16 and April 17, 2006, apparently triggered landslide movement, and is in part a result of the significant snow and rain that fell on April 6,” the UGS report on the Sunset Drive landslide said.
Steve Garside, assistant city manager for Layton, said the Sunset Drive landslide was partially due to homeowner mistakes — one homeowner dug out part of their land to put in an in-ground trampoline for their children.
“When you pull the dirt away from the downhill side of your foundation, so there’s nothing holding the foundation back, that causes a little bit of a problem,” Garside said.
Nowadays, if you head to the 1800 block of East Sunset Drive, you’ll see two empty lots. The home that once stood at 1843 East Sunset Drive is no more: the home sat squarely on the scarp — or the edge of a landslide — during the 2006 slide. With the foundation badly damaged, the house had to be removed.
To the southwest of Sunset Drive, you’ll find another area of Layton where homes once stood.
In August 2001, a landslide along Heather Drive hit six homes, causing over $1 million in damages and forcing evacuations, according to a UGS report. Heather Drive is located on a slope perched above South Fork Kays Creek.
The Heather Drive slide happened slowly over a few years, according to the same report. One homeowner began to see cracks in his home’s foundation in 1998. Another homeowner fixed a driveway in July 2000 and noticed the ground slowly shift for a year.
Over August, homes along the northern edge of the road slowly slid away from the road, leaving a gap of several feet between Heather Drive and the sinking homes. The slide also damaged buried water and gas lines, which were shut off while the homes above creaked and popped from the slow-moving slide, the UGS report said.
Three houses were moved off the landslide while three others were torn down.
Steve Garside, assistant city manager for Layton, said the homes lost in the Heather Drive landslide had been there for years, which made the slide all that more surprising when it happened.
“(Those homes) were actually built when the town of East Layton existed, and East Layton became a part of Layton City in ‘81, and so obviously, those homes had been there for a long time,” Garside told The Tribune.
Months before the 2006 Sunset Drive slide in Layton, a child in South Weber was injured when a fast-moving landslide hit the back of a home before bursting through a wall, a UGS report says. On top of the bluff where the slide started was a pond in a gravel pit, and officials found the bluff being saturated with water was one of the main factors in creating the slide.
Recent Slides
Garside said Layton continues to make improvements to mitigate landslide risk. Things like debris basins near the mouths of canyons can reduce potential damage if chunks of earth start flowing through creeks of the mountains.
“We always know that Mother Nature wins, as we say, so the best thing that we’ve done is try to make sure that our storm drain system will handle what is out there,” he said.
But even with mitigation, landslides are still largely unpredictable. Last month, a Layton home on Hidden Hollow Drive was evacuated after a resident heard water running underneath the pavement. Over the next several weeks, the earth shifted into the home, and according to UGS, two other homes are potentially threatened in the same slide.
In eastern Layton, another slide took place near Hobbs Creek Drive the same month. Despite the slide, a UGS report says no structures were damaged, though the bottom of the slide does appear to be close to a home.
One building was destroyed and two people were injured during a landslide in Fruit Heights last month. The leveled building was not a home, and a UGS report said the landslide was stable, though it could potentially move again with enough precipitation.
Like floods, landslides depend on weather
Garside said the area’s landslide risk would, like with flooding, depend in part on the weather. The sudden runoff triggered the 1983 floods and landslides, and a similar temperature fluctuation would be potentially harmful.
Layton City was initially concerned about snow in mid-elevations, Garside said, but much of that snow has melted off in recent weeks. But a good amount of snow has yet to melt off around Layton.
I’m “not excited to see the 80s yet,” Garside said, “but if we keep it low 80s into the 70s, we should be in good shape. And I’m not anticipating … any additional slides.” He added the caveat that more slides would be possible if heavy rainstorms were in the forecast.
But even given the region’s recent shift to temperatures in the high 70s and low 80s, a jump to hot weather doesn’t seem to be on the horizon, at least for now.
McDonald said this year has been hit or miss, as some slides the UGS expected to take place held steady while other areas thought to be more stable gave way. McDonald said the past three years of drought and a lack of groundwater could play a part, but there’s no way to be sure.
“It’s been a busy spring, but it hasn’t been as bad as it could have been,” McDonald said.
Correction: This story was updated to reflect that State Street became a river in Salt Lake City in 1983.
