A landslide warning system developed in Sitka is now available to the public as an online app, and work is underway to export the project to other communities in Southeast Alaska.
The app was unveiled at a meeting of the Sitka School Board Wednesday night (8-17-22).
Lisa Busch is the director of the Sitka Sound Science Center, which spearheaded the project. Busch is a 35-year resident of Sitka, and landslides were not on her radar – until a very bad day seven years ago.
“So this project got started in 2015, when we had a deadly landslide that killed our friends and family,” Busch said. “And I can say that I’ve been here 35 years and just never thought about landslides until then. As a big worry, mostly, we worried about tsunamis. And all of a sudden people had lots of concerns and lots of questions.”
What emerged from that disaster on August 18, 2015, was an interdisciplinary research program funded by a $2 million grant from the National Science Foundation. Partners ranged from the RAND Corporation which did social science, to the US Geological Survey and the National Weather Service which collected hard data, to the Sitka Tribe of Alaska, which gathered oral histories.
In all, there were 30 scientists and university researchers on the team. Busch said the final product had to serve a unique purpose: to give people enough information on if and when to act.
“And people said to us, and I think this is very Alaskan, they wanted to make their own decisions,” Busch said. “They wanted a digital dashboard, where they could go and look at the risk and then make their own choices about if they should evacuate.”
This is intentionally different from the tsunami warning system, which issues loud and insistent orders to evacuate – and is more or less binary: A big earthquake occurs and a tsunami is either there or it’s not. Landslides are the result of factors that are cumulative. In particular, how much rain has fallen – or is expected to fall – in a three-hour period. And unlike tsunamis, the landslide risk is not shared equally across town.
“We looked at where the more landslide prone areas are,” Busch explained, “and what part of Sitka is really most prone to landslides. And by the way, it’s not the whole town, it’s about 10-percent of our community. So when the landslides first happened, everybody said, ‘Well, we’re all in a landslide zone.’ That’s not true. About 10-percent of homes are in landslide areas.”
The Sitka landslide warning app is a web app, which opens in a web browser. It shows low, medium, and high risk, and generates a curve based on current conditions – plus the forecast – to anticipate risk up to three days into the future. It’s got recommendations on how to evaluate the information based on where you live, and what you should do if you decide to leave your home. The app is still being fine-tuned. Emergency planners hope to create messaging to help residents manage landslide risk moving forward.
“What the emergency response people would like is for you to find a buddy – a buddy system,” said Busch. “So my house is close to the water, and so I’m more prone to being hit by tsunamis. And my friend’s house is someplace else where I can go when there’s a tsunami warning. And then when there’s a landslide warning, my friend can come down to my house and be in my safe house. We’re saying go uphill for tsunamis, downhill for a landslide.”
Sitka is just the beginning, for what Busch hopes becomes a regional landslide warning system. Work is already in progress to create similar warning systems in Hoonah, Skagway, Klukwan, Craig, Kasaan, and Yakutat.