Sitka, AK

Science Center Objects

Recent Conditions

Instruments are used to monitor and detect changes in local conditions, including:

Data are updated every 60 minutes and displayed on graphs. Updates may be interrupted occasionally by instrument, computer, or network malfunctions.

Project Background

On August 18, 2015, heavy rainfall triggered around 60 landslides in and around the city of Sitka, AK. The landslides moved downslope rapidly; several were damaging and one of these demolished a home on South Kramer Avenue killing three people.

The USGS has installed instruments at a site near the initiation zone of the fatal Kramer Ave. landslide on Harbor Mountain, above Sitka. The sensors are installed in two soil pits on the edge of a steep hollow similar to the initiation zones of past landslides. Data collection at this site supports research on hydrologic factors that control landslide initiation. In many landslide-prone hillsides, infiltration of water from rainfall increases ground-water pressures. These elevated pressures can, in turn, induce landslide movement.

slope with grass and trees

Camouflaged rain gage mounted on post in clearing adjacent to soil pits at landslide monitoring site near Sitka, Alaska. (Credit: Rex Baum, USGS. Public domain.)

 

lake in foreground and mountains in background

Scar of the fatal Kramer Avenue landslide, which started on Harbor Mountain near Sitka, AK. (Credit: Ben Mirus, USGS. Public domain.)