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SALT LAKE CITY (AP) -- Last winter's heavy snowpack saturated soils and triggered several hundred landslides in Utah -- so many that "we stopped counting," said Francis Ashland of the Utah Geological Survey.
The year is shaping up to be the most active for landslides in more than 20 years, "and we have landslides still moving today," Ashland said Wednesday. "Everywhere we look, we see them."
Geologists are using instruments to keep track of 50 of the active slides, some of which could unleash with terrible force given the right conditions.
The hundreds of slides that let loose or were reactivated in 2005 are up from just three major landslides documented the previous year, when a lingering drought keep the activity to a minimum.
Together with spectacular floods and a deadly avalanche season, the year is shaping up as the most active for natural disasters in Utah since the hamlet of Thistle was taken out by a massive slide in 1983 in Spanish Fork canyon.
The disasters took at least a dozen lives. One boy was killed last March when an undercut bank of Kanab Creek collapsed, burying 10-year-old Josh Hutchings in 7 feet of soil. His was the year's only landslide fatality, but avalanches last winter took eight people, the highest death toll since Utah began keeping records in 1951.
Landslides hold even more deadly potential in the rapidly developing urban Wasatch Front corridor, said Richard Allis, director of the Utah Geological Survey.
Allis said a prime example of the danger was a mudslide last April that piled up against a row of four now-condemned Utah County townhouses. It was a slow-motion disaster, moving no faster than 11 inches a day, but a known hazard ignored by the developers and town of Cedar Hills. Angry home buyers said they never were warned.
"It is not uncommon for UGS concerns about slope instability to be downplayed by developers or even contested as not a relevant factor," Allis wrote in the most recent issue of Survey Notes, published last September.
"That's one we'll be watching closely when spring comes around," Allis said Wednesday in an interview. "Our main concern is that as the Salt Lake Valley and other urban areas grow, the growth tends to be in more vulnerable areas."
Ashland, Utah's leading landslide expert, calculated that slides caused more than $10 million in damage this year, mostly to houses uninsured for the hazard.
In one near-disaster last May, a 10-ton boulder crashed down onto a Provo neighborhood, clipping a guest house. It was unoccupied.
Allis warned neighbors there was little they could do to protect themselves because they lived against a steep mountainside with loose boulders. Geologists say the next earthquake will bring even more destructive and widespread landslides and rock falls to expensive neighborhoods strung along the Wasatch benches.
In all, a year of disasters killed at least a dozen people in Utah.
Avalanches killed three backcountry skiers, two friends on snowshoes and three on snowmobiles, said Bruce Temper, director of the Utah Avalanche Center.
Flooding drowned at least three people.
The first major flood hit southern Utah in January, when a storm dumped 10-12 inches of rain in 48 hours and turned the Santa Clara River into a raging torrent that swept away or damaged about 30 houses, making for spectacular television footage. Flooding returned to southern Utah in August, forcing dozens from their homes and washing out bridges.
Spring flooding was widespread across Utah but less spectacular, mostly covering farmers' fields and seeping into hundreds of basements. Notably, the Sevier River in central Utah spilled over its banks for much of the spring.
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Utah Geological Survey: http://geology.utah.gov/index.htm
survey Notes: http://geology.utah.gov/surveynotes/snt37-3.pdf
(Copyright 2005 by The Associated Press. All Rights Reserved.)
