Haines will soon have a better idea of its landslide risk, thanks to data collected by a ground-penetrating laser technology known as LiDAR. 

Maps of routes used during a LiDAR mapping in 2021 and 2022. (Alaska DNR image)

LiDAR allows scientists to detect soil types and disturbances below trees and other obstacles. Scientists with the state Division of Geological & Geophysical Surveys recently published data for the Haines area based on data collected in 2021 and 2022. 

“It’s been a game changer for scientists,” said Alaska Landslide Hazards Program Manager Martin Larsen about the use of LiDAR technology. 

Haines is among the first Alaska communities to have the LiDAR data released, but a full report that will translate the raw data into usable maps of risks and historic landslides won’t be released until the end of the summer. 

The Landslide Hazards Program was formed just a year and a half ago following Haines’ fatal 2020 slide. 

During the fall of 2021 and 2022, scientists flew a Bell Jet Helicopter with a laser scanner that sent up to 400,000 pulses per second into the ground to come up with the data. In all, the scan covered 471 square kilometers of terrain around Haines, concentrated around inhabited areas from Mud Bay and along the Haines Highway past Klukwan. 

Larsen said the final report based on the data will likely include a map of areas of town with the most susceptibility to landslides based on slope steepness and soil type. LiDAR can detect the different components of soil to sense which ones can absorb more water during major rain events, and which soils allow water to drain through. Sandy and rocky soils allow water to drain more easily, while silty and clay soils absorb more water and are thus more likely to slide. 

The final report set to be completed by September would also likely include maps of historic landslides that aren’t visible from above, since they’re blocked by vegetation. LiDAR allows scientists to peek through that vegetation to see historic landslides, which would indicate a likelihood of new ones. 

“That’s the great power of LiDAR,” said Larsen. 

Once the map is released, it’s up to the borough to decide what action, if any, to take.