Utah (ABC4) – Spring is here and Utah’s changing seasons often bring mother nature-related concerns.
According to the Utah Geological Survey, “landslide season is here,” should you be doing something to prepare?
What is a landslide? “A landslide is defined as the movement of a mass of rock, debris, or earth down a slope. Landslides are a type of “mass wasting,” which denotes any down-slope movement of soil and rock under the direct influence of gravity. The term “landslide” encompasses five modes of slope movement: falls, topples, slides, spreads, and flows,” as defined by the U.S. Geological Survey.
Landslides are common natural hazards in Utah, according to the Utah Geological Survey.
Most landslides in Utah occur during periods of rising groundwater levels due to excessive rainfall, snowmelt, or irrigation, and rockfalls. All these things are common in the spring and early summer months in the great Beehive State due to snowmelt, freeze-thaw cycles, and cloudburst storms.
Wade Mathews, Utah Divison of Emergency Management Public Information Officer tells ABC4 landslides throughout the state of Utah “tend to happen anywhere in the state there is an abundance of moisture and a slope.”
He says landslides more commonly happen where there is a burn scar.
In the event of a wildfire, the fire will ravage the ground, burn everything leaving behind a layer of ash. The fire heats or burns the soil so the soil cannot absorb the moisture on the top layer, leaving behind what officials call a burn scar.
This burn scar soil contributes to the potential for a landslide in a spring storm, Mathews adds.
Utah landslides can happen from “Northern Utah to Southern Utah, everywhere in between,” Mathews shares. He says the more urban the area of a landslide the more damage.
“We will see a greater impact in urban areas where there is more density, more houses,” Mathews tells ABC4. “That is where we will see more damage.”
Landslides still occur and cause damage in rural areas of the state but with things more spread out, Mathews says they don’t cause as much damage.
What, if anything can be done to prevent a landslide from happening?
Many hillslopes are prone to landsliding, particularly where development has taken place on existing landslides or where grading has modified a slope and reduced its stability, the Utah Geological Survey says.
“In Utah, nearly all recent landslides have occurred as reactivations of pre-existing landslides. Therefore, historical landslides, prehistoric landslides, and steep slopes prone to landsliding must be thoroughly investigated prior to development activities, along with regional groundwater and landscape and other irrigation activities,” as stated by the survey.
When considering development on a hillslope or adjacent area property, owners should consult with local planning and building officials.
If landslide hazards are present, the professionals should disclose the hazards and provide appropriate recommendations for grading, groundwater control, project design, and construction that will reduce the hazards, the survey adds.
Excessive irrigation can easily cause a neighbor near or on a slope to lose their home from a landslide. According to the Utah Geological Survey, smart irrigation controllers that adjust the amount of water applied to landscapes based on weather, plant/turf, and soil data, can significantly reduce the amount of excess water that percolates through the soil as groundwater and save money.
In the event of a wildfire and burn scar landslide, Mathews says replacing vegetation so things can grow again will help eliminate the potential for landslides by holding the soil back.
He says the best thing to do to prepare is “be ready to act quickly in that situation, be aware of the hazards of where you live.”
“The best thing to do is get out of the way,” Mathews says often times there is not a landslide warning. He says if you have any type of warning you have to “get about of the way, evacuate, leave the area.”