Geologists Keeping Eye on Utah's Active Landslides

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SALT LAKE CITY (AP) -- State geologists are watching 30 active landslides in northern Utah, some of them creeping downhill by inches each day. The danger is that they could pick up speed and unleash a torrent of mud and debris.

The danger of flooding and landslides will peak in about a month, when warm temperatures combine with mountain snowmelt, they said Tuesday. Adding heavy rain to the mix would guarantee problems.

"We're looking at one of the wettest years on record, particularly since March 1, and we're not done with it yet," Francis Ashland, a landslide specialist for the Utah Geological Survey, said Tuesday as skies cleared over Utah.

Snowbird ski resort reported 16 inches of snowfall from a storm that lingered over northern Utah on Monday and overnight. It also brought snow and rain to the Wasatch Front, adding to groundwater levels that Ashland said were approaching record levels.

"Really that's what triggers movement of soil and debris," he said.

Brian McInerney, a National Weather Service hydrologist, said streams throughout northern Utah were picking up volume. He said warming temperatures expected this week "could bring things up to bankful by the weekend."

McInerney said he didn't expect many streams to jump their banks until temperatures reached into the 80s, or until overnight mountain temperatures stay above freezing.

Some geologists were inspecting known landslide dangers on Tuesday, although there were no immediate reports of any slides moving faster than inches a day.

The landslide danger is most acute in Morgan and Cache counties, Ashland said.

A mudslide destroyed a South Weber house last week, forcing a temporary evacuation of 15 other neighbors for safety. An irrigation canal and retention pond were being investigated as the likely cause of the April 9 mudslide. Officials say the hill has stabilized.

Last year also was active for landslides. The Utah Geological Survey said it was aware of hundreds of slides in 2005 -- so many it stopped counting. That was up from just three major landslides the previous year, when a lingering drought keep the activity to a minimum.

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Utah Geological Survey: http://geology.utah.gov/index.htm