The Assembly wants the city to invest in landslide research beyond the Kramer Avenue area. Alaska’s Division of Geological and Geophysical Surveys partnered with the Coast Guard to create this digital surface model of North and South Kramer landslide area, as part of Sitka’s GeoTask Force. (From GeoTask Force Summary report)
At their meeting last night, the Sitka Assembly broadened the city’s commitment to landslide risk assessment. They approved a community-wide mapping project and an analysis of the Gary Paxton Industrial Park. And if their deliberations had a central question, it was this: Given the land shortage in Sitka, does establishing “risk zones” hamper future development? Basically, how much is too much when it comes to landslide research?
It’s hard to put into words just how much the August 18th landslides changed Sitkans and their relationship to the land.
Take Assembly member Matthew Hunter. The lifelong Sitkan mentioned how he accompanied a Department of Transportation geologist to survey the South Kramer Avenue area.
“Hiking up around the landslide immediately after the event, we got to talking and [the geologist] said, ‘You see all the flat area along the shorelines. That’s all landslide deposit.’ So, you wait long enough and something’s going to fall. Be it a tree or a rock or a hillside,” Hunter said. “I guess it opened my eyes – opened all of our eyes – to that risk.”
An illustration from the geotechnical study commissioned by Sitka in the aftermath of the August 18, 2015 landslides. Geologist LaPrade confirmed that there are no “no-risk” zones below Harbor Mountain.
But landslide risk is difficult to quantify without scientific research and data collection. In the wake of landslide, the Sitka Sound Science Center (SSSC) coordinated a GeoTask Force to pool landslide research from NASA, the U.S. Forest Service, and a variety of other federal and state agencies.
Click here to see the GeoTask Force summary report.
This table shows that an anomalous precipitable water values swept over Baranof Island the morning of August 18th, 140% of normal for late August. (Image from the National Weather Service, GeoTask Force Report)
Tori O’Connell, Research Director at SSSC, told the Assembly that once of the major conclusions by the task force is that the rain event that caused the landslide (three inches in six hours) is rare, happening every 45 years.
O’Connell also spoke about how NASA’s jet propulsion lab flew their P-band radar system, called AirMOSS, over Sitka twice to ascertain any further creep of our slide area.
SSSC is now working with National Weather Service to develop a warning system for landslides. O’Connell said, “You might have noticed that, since the landslide, the National Weather Service hasn’t included landslide warnings in their weather report, on the marine weather. The hope is that with siting more weather stations, the modeling can make these warnings more specific.”
With specificity in mind, the Assembly considered a resolution to develop a community-wide hazard map for Sitka. Similar to the South Kramer landslide report, prepared by geotechnical expert Bill Laprade over the winter, this report would do a similar analysis along the entire road system and map low, medium, and high risk areas.
Click here for Shannon & Wilson’s full South Kramer Avenue report.
Shannon & Wilson, Laprade’s firm, estimated a community-wide report would cost $150,000. Mayor Mim McConnell felt this was the more affordable option than going parcel by parcel. The South Kramer report alone cost $45,000. “There’s people that maybe would want to know this, but maybe would not be able to afford to have a study done [on their property]. And I think that would not be very fair,” McConnell said.
The South Kramer landslide tore through the Benchlands subdivision, claiming the lives of three men and destroying property. (Credit: US Coast Guard)
The pros of mapping are pretty obvious: enhancing safety of people and property. To protect the city from liability, attorney David Bruce even suggested a critical area ordinance, which would establish regulations for developing at-risk areas. For that, you need a map.
But the cons are manifold too. “Some of the cons could possibly be impacts on property value and future sales of property, possibile limitations on use of property or rights to property, and then certainly there could be limitations or impacts on development costs,” said Meagan Bosak, Community Planning and Development Director.
Assembly member Steven Eisenbeisz worried that in pursuing the information, the city would one day order people to abandon their homes or eliminate land for development altogether. Bosak assured him that regulations of any kind would come well after the mapping process.
And Assembly member Bob Potrzuski had this to say.
I’ve also had those same thoughts, Steven. It keeps coming back to me though, that, if I don’t know that I live in a risky area, I can’t make that decision in my own whether to stay there or not. In the discussions I’ve had, I don’t foresee the city moving people out of their homes. But again, if I’ve got a family, I think I want to know.
That comment steered the Assembly towards unanimous support of a community-wide hazard map on first and final reading.
There’s state forces behind this project too. Alaska’s Division of Geological and Geophysical Surveys (DGGS) requested FEMA conduct a multi-hazard assessment, that would include landslide mapping, avalanche, and riverine flooding hazards. It remains to be seen whether FEMA would oversee – and possibly fund – this project, but a map won’t be created anytime soon.
A debris flow along Sawmill Creek Road damaged GPIP’s administrative building. (Photo from GeoTask Force report)
The Assembly’s next item of business was to award a contract to Shannon & Wilson to perform a debris flow/risk analysis at the Gary Paxton Industrial Park. The contract is not to exceed $65,505 and would be paid for with GPIP’s undesignated working capital.
GPIP’s administrative building, which was damaged by the August 18th landslide, is up for sale.
City Administrator Mark Gorman said the city would not sell that or any other building without a risk assessment first. “Our economy is struggling. We have an opportunity to start moving property again in the park and it’s not going to happen unless we do the risk mapping.”
Eisenbeisz then asked, “Who is telling us this is a must do?” City Attorney Robin Schmid chimed in, “I am.” She commented, “Trying to protect the assets of the city is my job. And we’ve got a building down there that was damaged by a landslide. It just wouldn’t be prudent at all to turnaround and sell it and have another slide hit it. We’d be looking at liability.”
Assembly member Aaron Swanson asked why, if a community-wide assessment is on the horizon, the city should spend GPIP’s funds on this project. Gorman reasoned that this analysis would be more specific and offer designs for mitigation projects.
In the end, the Assembly voted to award the contract 5-2, with Eisenbeisz and Swanson opposed.
With these proposals, the Assembly continues to build upon the hard lessons learned from the August 18th landslides. Their hope is that, even if the mountains come down, the city has done the work to protect people and property down below.
A previous version of this story misstated that Hunter went up Harbor Mountain with geotechnical expert Bill Laprade immediately following the landslide. KCAW regrets this error.
